Improved photocatalytic efficiency and stability of CdS/ZnO shell/core nanoarrays with high coverage and enhanced interface combination

Photocatalytic hydrogen production of CdS/ZnO shell/core nanoarrays were investigated by combining the sensitization and calcining techniques. Long single crystal ZnO nanoarrays hydrothermally grown on FTO were fully covered with CdS using an optimized chemical bath deposition method. Heating treatment not only improved the interface connection and CdS crystallinity but also formed a (Cd_0.8Zn_0.2)S buffer layer between ZnO and CdS. The CdS/ZnO shell/core arrays showed gradually enhanced photocatalytic activity with raising the calcining temperature. This is predominantly attributed to the improved CdS crystallinity and the resultant (Cd_0.8Zn_0.2)S. The (Cd_0.8Zn_0.2)S buffer layer formed by calcining shows dramatic effect on the photocatalytic activity and stability. The CdS/ZnO shell/core arrays calcined at 550 °C exhibits the optimized photocurrent density of 5.1 mA cm^?2 and a photocatalytic stability over 12 h under visible-light irradiation.     

CdCl2-assisting heat-treatment: Enhanced photoelectrocatalytic hydrogen generation and stability of CdS/ZnO nanoheterojunction arrays

Hydrogen generation efficiency and stability of the photoelectrocatalytic (PEC) water splitting relate closely to the crystallinity and the interface structure of the photoanodes. Here we demonstrated a feasible strategy for improving the cystallinity and interface quality of the ZnO/CdS nanoheterojunction arrays (NHAs) via CdCl₂-assisting post-treatment. CdCl₂ treatment was found to promote the recrystallization and densification of the CdS shell layer, the formation of the Zn_xCd_1-xS intermediate layer between ZnO and CdS, and the creation of an intermediate band (IB) in the forbidden band of CdS due to the high-density Cl_S states. Meanwhile, the annealing temperature was also lowered from 550 °C to 430 °C with the assistance of CdCl₂ treatment. These improvements facilitate the seperation and transport of the photogenerated carriers and extends the light absorption range, resulting in extremely enhanced photocatalytic current and stability. Consequently, the photocatalytic currency reaches to 22 mA cm^?2 under the 100 mW cm^?2 illumination with the xenon lamp (λ > 420 nm), which is nearly two times larger than that annealed solely at 550 °C but without CdCl₂ treatment. The photocatalytic current remains 92% of the initial value after 20-h photocatalytic test.     

Hydrogenated CdS nanorods arrays/FTO film: A highly stable photocatalyst for photocatalytic H2 production

To improve the photocorrosion of CdS nanorod arrays (CdS NRAs), we have designed a simple and facile treatment method of in-situ hydrogenation to fabricate CdS@SnS/SnO₂ heterostructure on fluorine-doped tin oxide glass, which is a highly photostable hydrogenated CdS-based film photocatalyst (CdS NRAs-H₂). Over a 25-h long time irradiation, the total photocatalytic hydrogen production of hydrogenated CdS NRAs is almost 2.0 times higher than that of un-hydrogenated CdS NRAs. Moreover, the average hydrogen production rate of CdS NRAs-H₂ can steadily maintain at 23.75 μmol cm^?2 h^?1 with 102% of retention rate after 5 reaction cycles, while they are only 6.13 μmol cm^?2 h^?1 with 30% of retention rate for un-hydrogenated common CdS NRAs. The photocatalytic mechanism on enhanced activity and stability for hydrogenated CdS NRAs photocatalyst is also investigated and discussed in detail.     

Earth abundant ZnO/CdS/CuSbS2 core-shell nanowire arrays as highly efficient photoanode for hydrogen evolution

CuSbS₂ is regarded as a promising photo-absorber for solar energy conversion due to its proper bandgap, high absorptivity and earth abundance. Herein, novel low-cost ZnO/CdS/CuSbS₂ core-shell nanowire arrays were constructed as photoanode for hydrogen evolution through non-aqueous electrodeposition and cation exchange. The nanowire demonstrates even and compact multilayer structure. The optimal ZnO/CdS/CuSbS₂ photoanode achieves a photocurrent of 6.48 mA/cm² at 0 V versus Ag/AgCl and the remarkable IPCE value with approximately 52% at 480 nm in an electrolyte solution containing 0.35 mol/L Na₂SO₃ and 0.25 mol/L Na₂S. It also exhibited a good stability, maintained 87.9% of the initial current after 1 h measurement. The high performance benefits from well-crystalline and compact multilayer structure, high absorptivity of CuSbS₂ and CdS, p-n junction formed between CdS and CuSbS₂ which promotes the electron-hole separation and ZnO nanowire array as three dimensional scaffolds for electron percolation pathway. This work suggests the potential applications of low-cost p-n junction core-shell nanowire arrays as a highly efficient photoanode for hydrogen evolution in oil-field waste water with reductive sulfide.     

Photodeposited-metal/CdS/ZnO heterostructures for solar photocatalytic hydrogen production under different conditions

In this study, photocatalytic hydrogen production over metal-incorporated CdS and ZnO (M/CdS/ZnO) nanocomposites under simulated solar light illumination was investigated. M/CdS/ZnO samples were synthesized by photodepositing a metal into CdS/ZnO powders. All photocatalysts showed increased hydrogen production with an increase in the light exposure time. The M/CdS/ZnO samples exhibited better hydrogen production yields than the CdS/ZnO nanocomposites, which in turn showed higher hydrogen production yields than pure ZnO did. The hydrogen production yields of the CdS/ZnO samples increased as the CdS/ZnO weight ratio increased from 0.01 to 0.10. However, they decreased with further increases in CdS loading, although the light absorption edges of the CdS/ZnO samples were further extended to the visible region. Pt/CdS/ZnO and Pd/CdS/ZnO exhibited similar hydrogen production yields, which were higher than the Ni/CdS/ZnO yield. The hydrogen production yield of Pt (0.5%)/CdS/ZnO was higher than that of Pt (0.1%)/CdS/ZnO. Notably, the hydrogen production yield of CdS/Pt/ZnO was lower than that of Pt/CdS/ZnO. Among three different electron donors (Na₂S + Na₂SO₃, methanol, and lactic acid solutions), the Na₂S + Na₂SO₃ solution led to the highest hydrogen production yield. A tentative mechanism for photocatalytic hydrogen production over M/CdS/ZnO nanocomposites under solar light irradiation, using a Na₂S + Na₂SO₃ solution as an electron donor, was proposed. In summary, M/CdS/ZnO photocatalysts can be utilized efficiently for photocatalytic hydrogen production with solar light exposure through proper control of operating parameters.     

Design and preparation of CdS/H-3D-TiO2/Pt-wire photocatalysis system with enhanced visible-light driven H2 evolution

In recent years, tremendous efforts have been devoted to develop new photocatalyst with wide spectrum response for H₂ generation from water or aqueous solution. In this work, CdS nanoparticles (NPs) have been immobilized on hydrogenated three-dimensional (3D) branched TiO₂ nanorod arrays, resulting in a highly efficient photocatalyst, i.e, CdS/H-3D-TiO₂. In addition, electrochemical reduction of H⁺ ion is identified as a limiting step in the photocatalytic generation of H₂ at this catalyst, while here a Pt wired photocatalysis system (CdS/H-3D-TiO₂/Pt-wire) is designed to overcome this barrier. Without the application of potential bias, visible light photocatalytic hydrogen production rate of CdS/H-3D-TiO₂/Pt-wire is 18.42 μmol cm^?2 h^?1, which is 11.2 times that of CdS/H-3D-TiO₂ without Pt (1.64 μmol cm^?2 h^?1). The Pt wire acts as an electron super highway between the FTO substrate and H⁺ ions to evacuate the generated electrons to H⁺ ions and catalyze the reduction reaction and consequently generate H₂ gas. This work successfully offers a novel direction for dramatic improvement in H₂ generation efficiency in photocatalysis field.     

Enhanced photoelectrochemical water splitting in hierarchical porous ZnO/Reduced graphene oxide nanocomposite synthesized by sol-gel method

Today the utilization of solar energy to split water and its conversion to hydrogen and oxygen has been considered as a powerful way to solve the environmental crisis. Hierarchical porous nanostructured ZnO and ZnO/reduced graphene oxide (rGO) composite photoanodes are synthesized by innovated sol-gel method using triethylenetetramine (TETA) as a stabilizer. The hierarchical porous ZnO structure containing large agglomerates each consisting of tiny nanoparticles are formed. The X-ray diffraction analysis and Raman spectroscopy confirm the in-situ reduction of graphene oxide sheets during synthesis and formation of ZnO/rGO nanocomposite. Although the band gap and transmittance of the porous nanocomposites do not dramatically change by rGO addition, the main photoluminescence peak quenches entirely showing prolonging exciton lifetime. The ZnO/rGO porous structure achieved remarkably improved current density (1.02 mA cm^?2 at 1.5 V vs. Ag/AgCl) in 1 wt% rGO, up to 12 times higher compared to the bare ZnO (0.09 mA cm^?2 at 1.5 V vs. Ag/AgCl), which attributes to positive role of ZnO hierarchical porous structure and rGO electron separation/transportation. These findings provide new insights into the broad applicability of this methodology for promising future semiconductor/graphene composite in the field of photoelectrochemical water splitting.     

Hierarchically self-assembled ZnO architectures: Establishing light trapping networks for effective photoelectrochemical water splitting

Here we develop photoanodes based on hierarchical zinc oxide (ZnO) nanostructures such as vertically aligned nanorods (NR), nanorods interconnected by thin nanosheets (NR@TN) and nanorods interconnected by dense nanosheets (NR@DN). The morphological variations were successfully controlled by secondary growth time and the plausible formation mechanisms of these hierarchical ZnO architectures were explained based on the experiment analysis. Under simulated light illumination (AM 1.5, 100 mW cm^?2), NR@TN produced a photocurrent density of 0.62 mA/cm² at 1.23 V vs. reversible hydrogen electrode (vs. RHE). Importantly, 35% enrichment in photoconversion efficiency was observed for NR@TN at much lower bias potential (0.77 V vs. RHE) compared with NR (0.135%) and NR@DN (0.13% at 0.82 V vs. RHE). Key to the improved performance is believed to be synergetic effects of excellent light-trapping characteristics and the large surface-to-volume ratios due to the nanosheet structures. The nanorod connected with thin nanosheet structures improved the efficiency by means of improved charge transfer across the nanostructure/electrolyte interfaces, and efficient charge transport within the material. We believe that the hierarchical ZnO structures can be used in conjunction with doping and/or sensitization to promote the photoelectrochemical (PEC) performance. Further, the ZnO nanorod interconnected with nanosheets morphology presented in this article is extendable to other metal oxide semiconductors to establish a universal protocol for the development of high performance photoanodes in the field of PEC water splitting.     

Carbon black / PTFE composite hydrophobic gas diffusion layers for a water-absorbing porous electrolyte electrolysis cell

The characteristics of a water-absorbing porous electrolyte electrolysis cell, in which pressurized water is injected directly into the electrolyte layer, are investigated. High water support force is required for the gas diffusion layer (GDL) in this novel cell design, and therefore here we report a new type of hydrophobic GDL comprising an acetylene black (AB) and poly(tetrafluoroethylene) (PTFE) composite film. The method of preparation of the AB/PTFE slurry, film formation methods, and the AB/PTFE weight ratio were investigated and optimized. The ball-milling and transfer method were suitable for preparing uniform AB/PTFE slurry and successfully covering AB/PTFE film without any cracks on micro-porous layer coated carbon paper, respectively. An investigation about different PTFE weight ratios against AB from 0.1 to 6 showed a serious trade-off character between electrical resistance R, gas permeability V′, and water support force P_lim. The 1/2.5 of AB/PTFE weight ratio was most optimal, which showed to have most equivalent R (2.5 Ω cm^?2), V′(136 mL atm^?1 cm^?2 min^?1), and P_lim (0.25 MPa). We also confirmed that fabricated GDL with optimal condition was worked as the blocking layer against water injected through electrolyte layer and pressurized by nitrogen gas, and as gas-permeation layer for generated hydrogen gas in water electrolysis test.     

Surface modification of aligned TiO2 nanotubes by Cu2O nanoparticles and their enhanced photo electrochemical properties and hydrogen generation application

In this work, we report the synthesis of cuprous oxide (Cu₂O) nanoparticles modified vertically oriented aligned titanium dioxide (TiO₂) nanotube arrays through wet chemical treatment of TiO₂ nanotubes and their multi-functional application as enhanced photo electrochemical and hydrogen generation. The synthesized samples were characterized by X-ray diffraction, SEM, TEM, and UV–Vis spectroscopy. The structural characterization revealed that the admixed Cu₂O nanoparticles on the TiO₂ surface did not alter its crystalline structure of vertically oriented aligned TiO₂ nanotube. The photocatalytic performance and hydrogen generation of as synthesized Cu₂O nanoparticles modified aligned TiO₂ nanotube was found to highly depend on the Cu₂O content. The optical characterizations reveal that the presence of Cu₂O nanoparticles extends its absorption into the visible region which improves the photocurrent density in comparison to pristine aligned TiO₂ nanotubes electrodes due to enhanced photoactivity and better charge separation. The optimum photocurrent density and hydrogen generation rate has been found to be 3.4 mA cm^?2 and 127.5 μmole cm^?2 h^?1 in 1 M Na₂SO₄ electrolyte solution under 1.5 AM solar irradiance of white light with illumination intensity of 100 mW cm^?2.     

Nitrogen doped carbon layer coated platinum electrocatalyst supported on carbon nanotubes with enhanced stability

Enhancement in durability of electrocatalyst is still one of the most important issues in polymer electrolyte fuel cells (PEFCs). Here, we report a structurally coated electrocatalyst supported on carbon nanotubes (CNT), in which platinum (Pt) nanoparticles are coated by nitrogen doped carbon (NC) layers. CNT/NC/Pt/NC shows comparable electrochemical surface area (ECSA) and oxygen reduction reaction (ORR) activity to the non-coated electrocatalyst (CNT/NC/Pt), indicating that NC layer on Pt nanoparticles almost negligibly affects the activities of electrocatalyst; while, CNT/NC/Pt/NC exhibits a higher Pt stability due to the unique structure, in which the Pt nanoparticles are stabilized by the NC layers and Pt aggregation is decelerated proved by TEM measurement. Maximum power density of CNT/NC/Pt/NC reached 604 mW cm^?2 with Pt loading of 0.1 mg_Pt cm^?2, which only decreases by 7% compared to CNT/NC/Pt (650 mW cm^?2). The electrochemical analysis and fuel cell test illustrate that NC layer on Pt nanoparticles enhances the durability without serious deterioration of fuel cell performance.     

Facile preparation of Pt/CdS photocatalyst by a modified photoreduction method with efficient hydrogen production

A series of 0.75 wt% Pt/CdS photocatalysts were successfully synthesized via a modified photoreduction process, with the assistance of a protective agent (polyvinylpyrrolidone, PVP) and/or structural inducer (NaI, NaBr, and NaCl). The physicochemical properties of the obtained 0.75 wt% Pt/CdS photocatalysts were characterized in more detailed. Their photocatalytic efficiencies were evaluated by visible-light photocatalytic hydrogen production. The results show that the photocatalytic activities of 0.75 wt% Pt/CdS photocatalysts for H₂ production mainly depend on the type of structural inducer. Furthermore, a suitable ratio of PVP/NaI is necessary to optimize the photocatalytic performance of Pt/CdS composites. Notably, 0.75 wt% Pt/CdS (PVP/NaI = 4:1) gains the highest hydrogen production activity with a rate of 1155.8 μmol h^?1, which is 1.8 times higher than that of 0.75 wt% Pt/CdS obtained from the traditional photoreduction method (640.9 μmol h^?1) and 17.3 times higher than that of the bare CdS sample (66.9 μmol h^?1). The as-prepared 0.75 wt% Pt/CdS photocatalyst (PVP/NaI = 4:1) also exhibits a good stability. An optimum ratio of PVP/NaI not only causes a decrease in particle size of Pt nanoparticles but also leads to an increase in BET specific surface area of Pt/CdS and an enhanced electron transfer capability of Pt nanoparticles, which should be responsible for the enhanced photocatalytic performance.     

Preparation of Cu(In,Ga)Se2 thin films from Cu–Se/In–Ga–Se precursors for high-efficiency solar cells

Improved preparation process of a device quality Cu(In,Ga)Se₂ (CIGS) thin film was proposed for production of CIGS solar cells. In–Ga–Se layer were deposited on Mo-coated soda-lime glass, and then the layer was exposed to Cu and Se fluxes to form Cu–Se/In–Ga–Se precursor film at substrate temperature of over 200°C. The precursor film was annealed in Se flux at substrate temperature of over 500°C to obtain high-quality CIGS film. The solar cell with a MgF₂/ITO/ZnO/CdS/CIGS/Mo/glass structure showed an efficiency of 17.5% (V_oc=0.634 V, J_sc=36.4 mA/cm², FF=0.756).     

Characterization and application of self-assembled thin films of polyelectrolytes/TiO2/CdSe for hydrogen production

Photocatalysis of water to produce hydrogen gas over titanium dioxide or other semiconductor films, known as water splitting, is a promising alternative using solar energy to obtain a clean fuel. Self-assembled thin films (SATFs) from the physical adsorption of polyelectrolytes and inorganic semiconductor nanoparticles are created by an inexpensive and non-polluting process that gives films with high molecular organization. The aim of this work was to fabricate and characterize SATFs via the layer-by-layer technique using the polyelectrolytes polyallylamine hydrochloride (PAH), poly(acrylic acid) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in combination with titanium dioxide and CdSe nanoparticles and evaluate the application potential of these systems to produce hydrogen gas by solar radiation. The characterization of the SATFs showed that films with positive surface charge present favourable conditions for incorporation of negatively charged CdSe nanoparticles and that alkaline condition favour agglomeration of TiO₂ nanoparticles. The best system was composed of (PAH + CdSe) and (PEDOT:PSS + TiO₂ 100% anatase) in alkaline medium. With a hydrogen gas average production rate of 0.350 μmol h^?1 cm^?2, the maximum number of layers was optimized at 120 layers, beyond which there was a decrease in photocatalytic activity, reducing the average production rate to 0.07 with the SATF of 160 layers. Moreover, the presence of CdSe increased the hydrogen gas production by 75% when compared to the film containing only titanium dioxide.     

The heterogeneous electrolyte of CuFeO2 nano-flakes composited with flower-shaped ZnO for advanced solid oxide fuel cells

The flower-shaped ZnO was synthesized to form composite with the delafossite structure CuFeO₂. The composite heterojunction formed for the ZnO-CuFeO₂ composite material demonstrates a profound significance for exploring novel materials in solid oxide fuel cell (SOFC) field. At 550 °C, power outputs of 300 mW cm^?2 and 468 mW cm^?2 were achieved for SOFC devices using pure ZnO and composite with CuFeO₂ as the electrolytes, respectively. The composite showed a good performance at low temperatures, for instance, it showed a power output of 148 mW cm^?2 at 430 °C. The studies on photocurrent-time curves with visible light on/off irradiation provided an evidence for electron-hole separation. The heterojunctions separate holes and electrons, preventing short-circuiting while used in the SOFC device. These results demonstrate that introducing the heterojunctions in the electrolyte is an innovative approach for advanced SOFCs.     

Mo incorporated W18O49 nanofibers as robust electrocatalysts for high-efficiency hydrogen evolution

Creation of robust and stable electrocatalysts is a persistent objective for high-efficiency hydrogen evolution by water splitting. We present here the experimental realization of one-dimensional Mo incorporated W₁₈O₄₉ nanofibers (NFs) by a template-free solvothermal method. When utilized as electrocatalysts for hydrogen evolution through water splitting, the preliminary results demonstrate that the optimized catalytic electrode from 1 at% Mo doped W₁₈O₄₉ NFs yields an onset overpotential of 89 mV and Tafel slope of 49 mV dec^?1 as well as maximal exchange current density up to 1.60 × 10^?2 mA cm^?2. An overpotential as low as 462 mV is required to attain current density of 50 mA cm^?2 in comparison with 587 mV for pristine W₁₈O₄₉ NFs. Moreover, the Mo doped W₁₈O₄₉ NFs display relative stability by applying a potential of 503 mV and a current density of 80 mA cm^?2 over 24 h in 0.5 M H₂SO₄ aqueous solution, making them promising in practical applications.     

In situ observation of H2 dissociation on the ZnO (0001) surface under high pressure of hydrogen using ambient-pressure XPS

The interaction of H₂ molecules with a ZnO (0001) single crystal surface has been studied over a wide pressure (10^?6–0.25 Torr) and temperature (300–600 K) range using ambient pressure X-ray photoelectron spectroscopy (AP-XPS). ZnO is well-known for interstitial hydrogen and hydrogen atoms in ZnO are believed to be incorporated by the dissociative adsorption of H₂ molecules in the atmosphere and their subsequent diffusion into the bulk. The dissociative adsorption of H₂ has been investigated at elevated pressures because H₂ molecules are not dissociated on the ZnO single crystal surface under ultrahigh vacuum (UHV) conditions. When the pressure is increased to several mTorr, the dissociative adsorption of H₂ takes place to form OH bonds on the surface. At 0.25 Torr, the ZnO surface is saturated with H atoms and the coverage is estimated to be 1.1 × 10¹⁵ atoms/cm² at 300 K. At higher surface temperatures, the equilibrium between the dissociative adsorption of gas-phase H₂ molecules and the associative desorption of surface H atoms is established. While maintaining the equilibrium, the surface has been monitored successfully in situ by utilizing AP-XPS.     

Hierarchical molybdenum carbide/N-doped carbon as efficient electrocatalyst for hydrogen evolution reaction in alkaline solution

Development of highly-active and noble-metal-free electrocatalysts for hydrogen evolution reaction (HER) is of critical challenge for water splitting, and optimizing the structure and the composition of the relative materials is very necessary to obtain the high-quality catalysts. Herein, a novel molybdenum carbide/N-doped carbon (Mo₂C/NC) hybrid is fabricated by using the hierarchical polyaniline tube network as a carbon source and a reactive template, and the as-fabricated Mo₂C/NC hybrid possesses a uniform hierarchical tube structure. The coupling of the ultrafine Mo₂C nanoparticles and the N-doped carbon substrate provides the abundant active sites and accelerates the charge transfer process. The final Mo₂C/NC catalyst gives the excellent catalytic activity for HER in alkaline condition, which shows a lower overpotential of 142 mV at 10 mA cm^?2 and a small Tafel slope of 61 mV decade^?1 in 1 M KOH.     

CIS/CdS/ZnO/ZnO:Al modified photocathode for enhanced photoelectrochemical behavior under visible irradiation: Effects of pH and concentration of electrolyte solution

In this paper, the CuInS₂ films were firstly modified with CdS and CdS/ZnO/ZnO:Al/Au layers in order to improve the photoelectrochemical (PEC) water splitting efficiency. The CuInS₂ photoelectrode was synthesized by electrodeposition method as a facial and green method, on the FTO substrate. The effects of pH and concentration of Na₂S electrolyte solution on the photocurrent density of photoelectrode samples were studied. As a p-n junction photocathode, the CIS/CdS/ZnO/ZnO:Al/Au photoelectrode indicates the enhanced PEC activity. The photocurrent density of CIS/CdS/ZnO/ZnO:Al/Au photoelectrode reaches to 1.91 mA/cm², while is about 2.5 times higher than that for CuInS₂ film at pH = 8 (−0.6 V vs Ag/AgCl). The formation of a p-n junction at the CuInS₂ photoelectrode surface not only reduces the recombination of electron-hole pairs but also increases the PEC response and water splitting performance of the as-prepared CIS/CdS/ZnO/ZnO:Al/Au photoelectrode.     

Platinum nanoparticles deposited nitrogen-doped carbon nanofiber derived from bacterial cellulose for hydrogen evolution reaction

The nitrogen-doped carbon nanofiber derived from low and high proportion polyaniline doped bacterial cellulose (BC) was obtained via polymerization followed by pyrolysis. The resulting products were named LN-BC and HN-BC accordingly. Platinum nanoparticles modified LN-BC and HN-BC was then prepared (Pt@LN-BC and Pt@HN-BC) via electrochemical deposition. The morphologies of LN-BC and HN-BC indicated that the BC lost its nanowire structure after polyaniline modification and pyrolysis under nitrogen atmosphere. Platinum nanoparticles with diameters ranging from 3 to 5 nm can be well dispersed in the HN-BC support. The HER performance of Pt@LN-BC and Pt@HN-BC was fully investigated. Electrochemical results showed that the Pt-based catalysts had better HER activity than the Pt free catalysts in acid, indicating the HER activity was mainly from Pt. Besides, Pt@HN-BC had better HER activity than Pt@LN-BC in acid, suggesting N-doping rate was an important factor in enhancing HER activity. And the 10Pt@HN-BC (deposition for 10 s) with 4.38 wt% Pt loading was the best HER catalyst among the Pt@HN-BC. The onset potential (@ ?1 mA cm^?2) and overpotential (@ ?10 mA cm^?2) of the 10Pt@HN-BC in 0.5 M H₂SO₄ is ?18 and ?47 mV, respectively. The corresponding Tafel slope was ?35 mV dec^?1, which is quite comparable to that of Pt/C (10 wt%). The electrochemical double layer capacitance (C_dl) and turnover frequency (TOF) were estimated and presented in the work. Long-term stability test confirmed that the 10Pt@HN-BC had excellent stability, which was important for practical application.