Synthesis of ultrafine low loading Pd–Cu alloy catalysts supported on graphene with excellent electrocatalytic performance for formic acid oxidation

Here, surfactant free composite catalysts (Pd–Cu/rGO) with Pd–Cu alloy nanoparticles uniformly distributed on graphene sheets are successfully prepared via a facile hydrothermal approach. Compared with pure Pd/rGO catalyst, the introduction of copper could dramatically enhance the performance of the catalyst in the electrocatalytic formic acid oxidation (FAO) due to the strain effect and the ligand effect. With the optimized atomic ratio of 3:1 between palladium and copper, the alloy nanoparticle shows the smallest size of 2.12 nm, thus endowing the composite catalyst with highest catalytic efficiency. With Pd load as low as 14.5%, a maximum mass current density of 1580 mA mg_Pd⁻¹, and residual current of 69.93 mA mg_Pd⁻¹ at 3000 s was achieved with our Pd₃Cu₁/rGO catalyst in the electrocatalytic FAO process.     

A robust electrocatalytic activity and stability of Pd electrocatalyst derived from carbon coating

Palladium (Pd) as an efficient anodic catalyst has been extensively investigated in direct formic acid fuel cells (DFAFCs); while, Pd catalyst is electrochemically unstable in acidic electrolyte resulting in low stability retarding the widespread application of DFAFCs. In this study, a new method is invented to prevent the Pd nanoparticles from rapid dissolution by carbon layer originated from the carbonization of glucose. Ascribing to the presence of carbon layer, Pd electrocatalyst demonstrates much higher stability in comparison with Pd electrocatalyst without carbon layer in the course of stability tests. Robust electrocatalytic activities toward formic acid and methanol/ethanol oxidation are observed for carbon-stabilized Pd electrocatalyst resulted from the higher content of metallic Pd atoms coming from the carbonization process, in which Pd (II) species are further reduced. Moreover, the fuel cell performance of carbon-stabilized Pd electrocatalyst reaches 90 mW cm_Pd⁻² measured with 1 M formic acid; while, power density of bare Pd electrocatalyst is only 74 mW cm_Pd⁻². This work highlights that carbon layer carbonized from glucose improves not only the stability of Pd electrocatalyst, but also the electrocatalytic activity.     

Zn-substituted MnCo2O4 nanostructure anchored over rGO for boosting the electrocatalytic performance towards methanol oxidation and oxygen evolution reaction (OER)

Mixed valence spinel oxides have emerged as an attractive and inexpensive anode electrocatalyst for water oxidation to replace noble metals based electrocatalysts. The present work demonstrates the facile synthesis of Zn substituted MnCo₂O₄ supported on 3D graphene prepared by simple hydrothermal technique and its application as an electrocatalyst for water oxidation and methanol oxidation. The physico-chemical properties of the nanocatalyst were studied using various microscopic, spectroscopic and diffraction analyses confirming the formation of the composite. The electrocatalytic performance of the prepared electrocatalyst was evaluated using potentiodynamic, potentiostatic and impedance techniques. The synthesized Zn_1-xMn_xCo₂O₄/rGO electrocatalyst with x = 0.2 and 0.4 offered the same onset potential and overpotential at 10 mA/cm². However, catalyst x = 0.4 delivered a higher current density indicating the superiority of the same over other compositions which is attributed to better kinetics that it possessed for OER as revealed by the smallest Tafel slope (80.6 mV dec⁻¹). The prepared electrocatalysts were tested for methanol oxidation in which electrocatalyst Zn_1-xMn_xCo₂O₄/rGO with x = 0.4 shows a better electrochemical performance in oxidizing methanol with the higher current density of 142.3 mA/cm². The above catalyst also revealed excellent stability and durability during both MOR and OER, suggesting that it can be utilized in practical applications.     

Solvothermal synthesis of Pd10–Ni45–Co45/rGO composites as novel electrocatalysts for enhancement of the performance of DBFC

In this research, three Pd decorated Ni and Co catalyst nanoparticle were synthesized on reduced graphene oxide (rGO) supports are synthesized through a facile solvothermal procedure. Borohydride oxidation reaction (BOR) activity and performance of prepared electrocatalysts respect to NaBH₄ oxidation is evaluated by various electrochemical techniques in the three-electrode and the fuel cell configuration. Among the prepared catalysts, Pd₁₀–Ni₄₅–Co₄₅/rGO exhibits the highest BOR activity. The cyclic voltammograms showed that the measured current at 0.5 V for the electrode of Pd₁₀–Ni₄₅–Co₄₅/rGO is as much as 108 mA cm⁻² higher than Pd₁₀–Ni₉₀/rGO and 185 mA cm⁻² higher than Pd₁₀Co₉₀/rGO. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectra were employed to study the morphology and crystal structure of the prepared catalyst. The results of DBFC test show that the Pd₁₀–Ni₄₅–Co₄₅/rGO nanoparticles as anodic catalyst, enhanced power density to 50.4 mW cm⁻² which is 10.5% and 45.2% higher than power density of DBFCs with Pd₁₀–Ni₉₀/rGO (45.6 mW cm⁻²) and Pd₁₀Co₉₀/rGO (34.7 mW cm⁻²) anode catalysts, respectively. These results indicate that the competency of operating procedure for assembling nickel alloys electrodes can improve the activity of the prepared catalysts for BOR considerably.     

Pd-Ni electrocatalysts for efficient ethanol oxidation reaction in alkaline electrolyte

Pd_xNi_y/C catalysts with high ethanol oxidation reaction (EOR) activity in alkaline solution have been prepared through a solution phase-based nanocapsule method. XRD and TEM show Pd_xNi_y nanoparticles with a small average diameter (2.4-3.2 nm) and narrow size distribution (1-6 nm) were homogeneously dispersed on carbon black XC-72 support. The EOR onset potential on Pd₄Ni₅/C (−801 mV vs. Hg/HgO) was observed shifted 180 mV more negative than that of Pd/C. Its exchange current density was 33 times higher than that of Pd/C (41.3 × 10⁻⁷ A/cm²vs. 1.24 × 10⁻⁷ A/cm²). After a 10,000-s chronoamperometry test at −0.5 V (vs Hg/HgO), the EOR mass activity of Pd₂Ni₃/C survived at 1.71 mA/mg, while that of Pd/C had dropped to 0, indicating Pd_xNi_y/C catalysts have a better ’detoxification’ ability for EOR than Pd/C. We propose that surface Ni could promote refreshing Pd active sites, thus enhancing the overall ethanol oxidation kinetics. The nanocapsule method is able to not only control over the diameter and size distribution of Pd-Ni particles, but also facilitate the formation of more efficient contacts between Pd and Ni on the catalyst surface, which is the key to improving the EOR activity.     

Controllable electrodeposition synthesis of Pd/TMxOy-rGO/CFP composite electrode for highly efficient methanol electro-oxidation

A novel and high-efficiency Pd/TM_xO_y-rGO/CFP (TM_xO_y = Co₃O₄, Mn₃O₄, Ni(OH)₂) electrocatalyst for directly integrated membrane electrode was synthesized by controllable cyclic voltammetry electrodeposition combined with hydrothermal process. The results showed excellent performance towards methanol oxidation reduction. The Pd/Co₃O₄-rGO/CFP as-prepared catalyst has the best electrocatalytic activity, and mass activity is 5181 mA·mg⁻¹_Pd, which is about 40 times and 4.3 times that of the commercial Pd/C and Pt/C catalyst (JM). It can be attributed that the small size of Pd nanoparticle, uniformity of distribution, and the synergistic interaction between transition metal oxide on the support surface and Pd nanoparticles. The prepared Pd/TM_xO_y-rGO/CFP composite electrode is a promising catalyst for integrated membrane electrode assembly of proton exchange membrane fuel cells in the future.     

Surfactant-free room temperature synthesis of PdxPty/C assisted by ultra-sonication as highly active and stable catalysts for formic acid oxidation

Formic acid oxidation is usually catalyzed on PdPt bimetallic catalysts, which are synthesized by co-reduction of noble metal precursors in the presence of high molecular capping agents. In this work, surfactant-free Pd_xPt_y/C catalysts are synthesized by H₂ reduction in ethylene glycol assisted with ultrasonication vibration at room temperature. Nanoparticle agglomeration in the course of preparation has been sufficiently curbed by strong mechanical ultrasonication instead of traditionally-employed surfactants. As a result, “clean” surfactant-free Pd_xPt_y/C catalysts necessitate only simple washing before collection. The catalysts are characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The compositionally optimized Pd₁₀₀Pt₁/C catalyst registers a mass activity of 3171 A g⁻¹ (Pt + Pd) for formic acid oxidation in 0.5 M H₂SO₄+0.5 M HCOOH, which lists one of the best results reported so far and surpasses that of a commercial Pd/C by 5.6 times. Stability of the catalysts is investigated by cyclic voltammetric as well as chronoamperometric evaluations. This work offers a convenient and environmentally benign room-temperature route to synthesize highly active and stable catalysts for formic acid oxidation.     

Ultrafine palladium nanoparticles anchored on NH2-functionalized reduced graphene oxide as efficient catalyst towards formic acid dehydrogenation

The development of active and stable catalyst is of significance for hydrogen generation from formic acid. Herein, a novel palladium catalyst with ultrafine metallic nanoparticles anchored on NH₂-functionalized reduced graphene oxide (NH₂-rGO) was synthesized by a facile wet chemical reduction process using sodium borohydride as the reducing agent. The TEM and XPS characterization results confirmed the successful functionalization of rGO with 3-aminopropyltriethoxysilane (APTES), which plays a very important role in evenly dispersing ultrafine Pd nanoparticles with a small average size of about 2.3 nm. As a result, the as-prepared Pd/NH₂-rGO catalyst exhibited excellent activity with a high initial turnover frequency of 767 h⁻¹ and 100% hydrogen selectivity, which was predominant among the currently available pure Pd catalysts towards formic acid dehydrogenation under room temperature.     

Aluminum supported palladium nanoparticles: Preparation,characterization and application for formic acid electrooxidation

Palladium nanoparticles were fabricated on the aluminum electrode (Pd/Al) by electrodeposition method through a single step potential from an aqueous solution of 1 mM Pd(NH₃)₄Cl₂. The electrochemical and physical characteristics of the Pd/Al were investigated by cyclic voltammetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) method. Electrochemical measurements in acidic solution indicate that Pd/Al exhibits significantly high electrochemical active surface area (18.32 cm²) with respect to Pd–Al (2.1 cm²) (electroless deposited) and bare Pd (0.28 cm²) electrodes. SEM images and XRD results show that the Pd particles are homogeneously deposited on the surface Al substrate in nanoparticles size between 30 and 50 nm with maximum Pd (111) plane at 2θ angles about of 39°. The Pd/Al was used as electrocatalyst for the oxidation of formic acid (FA) in 0.1 M H₂SO₄ solution. The cyclic voltammetry and chronoamperometry results show that the obtained electrocatalyst, Pd/Al, exhibits high catalytic activity and stability for the electrooxidation of FA. On the other hand, the Pd/Al electrocatalyst has higher catalytic activity for FA oxidation than the comparative Pd–Al and bare Pd electrodes and shows great potential as less expensive electrocatalyst for FA oxidation in direct formic acid fuel cells.     

Enhanced Electro-catalytic Activity of Nitrogen-doped Reduced Graphene Oxide Supported PdCu Nanoparticles for Formic Acid Electro-oxidation

Successful commercialization of direct formic acid fuel cells (DFAFCs) is restricted because of its apparent instability in acidic medium and high cost of typically noble metal based anode catalyst. To adequately address these key issues, in this work, a series of palladium-copper alloy catalyst supported on nitrogen-doped reduced graphene oxide (N-rGO) were synthesized via wet chemical reduction process. Several microscopic and spectroscopic techniques were employed to determine the crystal pattern, particle size, composition and morphology of the synthesized material. Electro-catalytic performance of the synthesized catalysts was carefully verified with respect to formic acid oxidation. All N-doped reduced graphene oxide (N-rGO) supported catalyst show enhanced catalytic activity in comparison to commercial Pd/C catalyst. Electrochemical study reveals precisely that Pd₇₅Cu₂₅/N-rGO catalysts have highest electro catalytic activity 1738 mA mg⁻¹_pd among all synthesized catalyst which is 3.67 times higher than commercial Pd/C catalyst. Pd₇₅Cu₂₅/N-rGO catalyst show lowest Tafel slope (119 mV dec⁻¹) and excellent stability after 250 potential cycles. These extensive studies signify that N-rGO support material can remarkably improve the catalytic activity and stability of the catalysts which may be due to outstanding electron transfer capability and synergy between PdCu metallic and N-rGO support. This work helps further design of alloy nanoparticles on N-rGO support as a highly active and stable catalyst for application in the fuel cell.     

Effect of cation substitution in MnCo2O4 spinel anchored over rGO for enhancing the electrocatalytic activity towards oxygen evolution reaction (OER)

Developing an efficient and durable electrocatalyst for catalyzing oxygen evolution reaction in electrochemical water splitting application is greatly desired and challenging. Herein, a simple and facile strategy was followed to prepare Ni-substituted MnCo₂O₄/rGO nanocomposite as an electrocatalyst for oxygen evolution reaction (OER). The structural and morphological analyses show the successful bonding between spinel-carbon hybrid. Nickel substitution and addition of rGO disclose a drastic change in the catalytic activity of the same towards OER. Among all the electrocatalysts, Mn_1-xNi_xCo₂O₄/rGO with x = 0.6 exhibits low overpotential of 250 and 290 mV for attaining the current density of 10 mA/cm² before and after potential cycling respectively. It also exhibits low onset potential of 1.48 V with a Tafel slope of value 78 mV/dec. The electrocatalyst also shows excellent stability, high ECSA and roughness factor (R_f) which are responsible for enhanced OER performance. These properties confirm that the present hybrid material would be an excellent electrocatalyst for catalyzing OER for hydrogen energy production.     

Pd electrodeposition on a novel substrate of reduced graphene oxide/ poly(melem-formaldehyde) nanocomposite as an active and stable catalyst for ethanol electrooxidation in alkaline media

Palladium nanoparticles (Pd NPs) were successfully electrodeposited on a reduced graphene oxide/poly(melem-formaldehyde) nanocomposite (rGO/PMF) NC as a catalyst for ethanol electrooxidation in alkaline media; melem was used as a nitrogen-rich source in the substrate structure for the first time. The specific surface area and average pore diameter of (rGO/PMF) NC were 481.61 m² gr^?1 and 10.23 nm, respectively. High nitrogen doping and structural defects improved the dispersion and anchoring of Pd NPs on (rGO/PMF) NC. The onset potential (E_onset) of Pd/(rGO/PMF) NC was shifted negatively to 110 mV, in comparison to Pd/rGO. Also, the current density and electrochemical active surface area (EASA) of Pd/(rGO/PMF) NC were enhanced to 44 mA cm^?2 and 67.58 m² gr^?1, respectively, as compared to Pd/rGO. Furthermore, the stability of Pd/(rGO/PMF)NC was indicated against ethanol oxidation intermediates during 7000 s. This work also produced a superior graphene-based material for direct ethanol fuel cell anode catalysts applications.     

Three-dimensional reduced graphene oxide–Mn3O4 nanosheet hybrid decorated with palladium nanoparticles for highly efficient hydrogen evolution

A three-dimensional (3D) reduced graphene oxide–Mn₃O₄ nanosheet (Mn₃O₄@rGO) hybrid was achieved by simple electrodeposition technique. Small palladium nanoparticle were homogeneously anchored onto Mn₃O₄@rGO substrate through the reduction of palladium salt. The interpenetrating network architecture of Mn₃O₄@rGO greatly inhibited the aggregation of 2D sheets of Mn₃O₄ and rGO, and the open 3D orientation of the Mn₃O₄@rGO hybrid nanosheets on the electrode facilitated both mass transport and electron transfer as well as maximally exposed active sites. The introduction of Mn₃O₄ enhanced the structural and electrochemical stability of rGO. The as-synthesized Pd/Mn₃O₄@rGO hybrid was employed as an electrocatalyst for electrocatalytic hydrogen evolution reaction (HER). The electrocatalyst showed a low overpotential of 20 mV at 10 mA cm^?2, a small Tafel slope of 48.2 mV dec^?1, and a large exchange current density of 0.59 mA cm^?2. Importantly, the catalyst possessed superior durability with 85.87% of catalytic activity after a long-time test (10 h). This work presents a simple and efficient stratagy to construct high-performance electrocatalysts for energy and environmental applications.     

Insight towards kinetics and stability of carbon supported Pd–Y2O3 as cathode catalyst for polymer electrolyte fuel cells

Pd–Y₂O₃ on carbon (Pd–Y₂O₃/C) in different mass ratios of Pd to Y₂O₃ (1:1, 2:1, 3:1) were prepared and subjected as cathode electrocatalyst for polymer electrolyte fuel cells (PEFC). X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to determine the structure, crystalline size and dispersion of Pd–Y₂O₃/C respectively. The electrochemical characterizations of the electrocatalysts were evaluated from Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV). These electrocatalysts were evaluated for their catalytic activity towards oxygen reduction reaction (ORR) in fuel cell. Pd₂–Y₂O₃/C catalyst shows higher power density of 325 mW cm^?2 than Pd₁–Y₂O₃/C, Pd₃–Y₂O₃/C and Pd/C.     

A “special” anhydrous system for the preparation of alloyed Pd1Ce0.5 nanonetworks catalyst supported on carbon nanotubes with high electrochemical oxidation activity for formic acid

Herein, Pd₁Ce_0.5 alloy nanonetworks (ANNs) on multi-walled carbon nanotubes (MWCNTs) supported bimetallic catalyst (referred to Pd₁Ce_0.5/MWCNTs-D) was prepared in deep eutectic solvents (DESs). The Pd₁Ce_0.5/MWCNTs-D catalyst shows remarkable catalytic performance toward formic acid oxidation (FAO) (1968.5 mA mg_Pd^?1) and better CO anti-poisoning capability compare with Pd/MWCNTs-D, Pd/MWCNTs-W (prepared in water) and commercial Pd/C catalysts. The excellent network structure and synergistic effect are the main reasons for the improvement of electrochemical activity of Pd₁Ce_0.5/MWCNTs-D catalyst. This study provides a new method for preparation of high performance Pd-based electrocatalysts for direct formic acid fuel cell (DFAFC) applications.     

One-pot synthesis of Pd20-xAux nanoparticles embedded in nitrogen doped graphene as high-performance electrocatalyst toward methanol oxidation

Mixed Pd–Au bimetallic nanoparticles embedded nitrogen doped graphene composites (PdAu/NG180) are explored for efficient electrocatalytic oxidation of methanol. A simple hydrothermal one-pot polyol method, involving simultaneous reduction of both Pd and Au, is utilized for the synthesis of Pd_20-xAu_x/NG180 (x wt % = 0, 5, 10 and 15). This method is of multiple advantages such as inexpensiveness, reagent-free and environment-friendly being surfactant free. The morphology, crystal structure and chemical composition of NG180, Pd/NG180 and Pd_20-xAu_x/NG180 catalysts are analyzed by XRD, FESEM-EDX, TEM, XPS and Raman spectroscopy methods. Electrocatalytic activities of PdAu/NG180 nanocomposites toward methanol oxidation reaction (MOR) in alkaline media are investigated by cyclic voltammetry, chronoamperometry and CO stripping measurements. Pd_20-xAu_x/NG180 exhibited an increase in the electroactive surface area of Pd to twice by the coexistence of Au. In cyclic voltammetry studies, Pd₁₀Au₁₀/NG180 catalyst exhibits highest peak current density for MOR and is 1.5 times highly efficient compared to Pd₂₀/NG180 with an enhanced shift in the onset potential by 140 mV to lower overpotentials. Besides, Pd₁₀Au₁₀/NG180 catalyst exhibited enhanced electroactive surface area and long-time durability in comparison to Pd₂₀/NG180 catalyst. The steady state current density for MOR observed with Pd₁₀Au₁₀/NG180 at the end of 4000 s (98 mA mg⁻¹_Pd) is higher than those observed with all the other catalysts at the end of mere 1000 s alone (97, 61, and 32 mA mg⁻¹_Pd). The promising high electrocatalytic activity of Pd₁₀Au₁₀/NG180 is well corroborated from CO stripping experiments that the specific adsorption of CO onto Pd₁₀Au₁₀/NG180 (0.71 C m⁻²) is merely half to that observed onto Pd₂₀/NG180 (1.49 C m⁻²).     

Electrodeposited graphene hybridized graphitic carbon nitride anchoring ultrafine palladium nanoparticles for remarkable methanol electrooxidation

Exploiting high performance electrocatalysts is crucial for the effective electrooxidation of methanol, although some barriers exist. Herein, we develop a hybrid support composed of graphitic carbon nitride (g-C₃N₄) and reduced graphene oxide (rGO) synergistically anchoring sufficient ultrafine palladium (Pd) nanoparticles via a simple one-step electrodeposition technique. The morphology and structure were characterized by scanning/transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy, which confirmed that the Pd nanoparticles were massively and uniformly dispersed on the support of g-C₃N₄@rGO with a the average particle size of 5.87 nm, deriving from the nitrogen in g-C₃N₄ contributing to the electron transport highway on the rGO nanosheet layer surface. Furthermore, electrochemical results suggested that the Pd/g-C₃N₄@rGO showed a high electrocatalytic efficiency for methanol oxidation with a high current density reached 0.131 mA cm⁻². Based on a novel approach to the g-C₃N₄@rGO hybrid nanostructure, this work offers a promising method for the design and synthesis for the superior performance methanol electrocatalyst.     

Electro-oxidation of ethylene glycol on PtCo metal synergy for direct ethylene glycol fuel cells: Reduced graphene oxide imparting a notable surface of action

Slow electro-oxidation reaction and low power output are two major limiting factors in successful commercialization of fuel cell technology. An efficient and stable electro-catalyst with effectual metal combination supported on a durable matrix may provide a viable solution to overcome these issues. The direct ethylene glycol fuel cell consisting of bimetallic anode catalysts are expected to lead out the high-power output issues. In the present paper, we emphasized on the synthesis of a high performing CO poisoning resistant Pt based binary anode catalysts for the electro-oxidation of ethylene glycol (EG) using a chemical reduction route. The electrocatalysts consists of PtCo alloy nanoparticles with different composition of Pt and Co, supported on reduced graphene oxide (rGO). Physical characterizations revealed the formation of bi-metallic catalysts within the size ranges from 2 nm to 3 nm. Electrochemical analysis revealed that Pt_xCo_y/rGO electrocatalyst with x: y molar ratio of 1:9 imparts the highest peak current and power density as compared to commercially available Pt/C and PtCo/C anode catalysts for ethylene glycol electro-oxidation. The power density (81.1 mW/cm²) obtained using Pt_xCo_y/rGO with x:y molar ratio of 1:9 metal catalyst in DEGFC is more than other synthesized catalysts at an operating temperature of 100 °C and the operating pressure of 1 bar with 2 M ethylene glycol as anode fuel and anode and cathode platinum metal loading of 2 mg/cm².     

Synthesis of high performing Cu0.31Ni0.69O/rGO hybrid for oxygen reduction reaction in alkaline medium

In this feature article, Cu_0.31Ni_0.69O nanoparticles were assembled on reduced graphene nanosheets (Cu_0.31Ni_0.69O/rGO) by a simple hydrothermal method. The structural characterizations confirm that the synthesized nanoparticles with an average size around 9 nm are densely and uniformly assembled on the reduced graphene oxide (rGO) nanosheets. The electrochemical measurements demonstrate that the as-synthesized Cu_0.31Ni_0.69O/rGO catalyst exhibits excellent catalytic performance for oxygen reduction reaction with high cathodic current density (2.08 × 10⁻⁴ mA/cm²), positive onset potential (−0.21 V), low H₂O₂ yielding rate (less than 2.5%) and long-term running stability. The rotating disk and rotating ring-disk electrode measurements proved that the oxygen reduction reaction occurs on Cu_0.31Ni_0.69O/rGO through a high efficient four-electron pathway. The Cu_0.31Ni_0.69O/rGO nanoparticles shows great potential to be promising noble metal-free catalyst for cathodes of alkaline fuel cells.     

Atomically dispersed palladium supported on nitrogen-doped mesoporous carbon for drastic electrocatalytic hydrogen evolution

The electrocatalysis of water to hydrogen is expected to play an essential and significant role in the development of future electrochemical energy conversion and storage technologies, together with the exploration of green energy. However, the high cost of noble metal catalysts remains a key challenge and it still requires further investigations to fabricate high mass activity and stable electrocatalysts. Herein, we report a facile and economical approach to achieve atomically dispersed palladium on the nitrogen-doped mesoporous carbon matrix (Pd₁/NMC) as the electrocatalyst for hydrogen evolution, which exhibits an overpotential of 37 and 118 mV at the current density of 10 and 100 mA cm^?2, respectively, superior to the commercial platinum/carbon (Pt/C) and palladium/carbon (Pd/C) catalysts. Moreover, the mass activity of the Pd₁/NMC catalyst surpasses that of Pt/C and Pd/C at 100 mV versus RHE in HER. Systematic characterizations demonstrate that the Pd atoms are atomically dispersed on the surface of NMC and stabilized by active nitrogen sites, inducing the isolated Pd atoms to form a favorable bivalent oxidation state. This method provides an atomic-level insights into preparing superior single-atom catalysts for energy-related applications and devices.