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1.
Electrochemical reduction of CO 2 (CO 2RR) into value-added products is a promising strategy to reduce energy consumption and solve environmental issues. Formic acid/formate is one of the high-value, easy-to-collect, and economically viable products. Herein, the reconstructed Bi 2O 2CO 3 nanosheets (BOC R NSs) are synthesized by an in situ electrochemical anion exchange strategy from Bi 2O 2SO 4 as a pre-catalyst. The BOC R NSs achieve a high formate Faradaic efficiency (FE formate) of 95.7% at −1.1 V versus reversible hydrogen electrode (vs. RHE), and maintain FE formate above 90% in a wide potential range from −0.8 to −1.5 V in H-cell. The in situ spectroscopic studies reveal that the obtained BOC R NSs undergo the anion exchange from Bi 2O 2SO 4 to Bi 2O 2CO 3 and further promote the self-reduction to metallic Bi to construct Bi/Bi O active site to facilitate the formation of OCHO * intermediate. This result demonstrates anion exchange strategy can be used to rational design high performance of the catalysts toward CO 2RR. 相似文献
2.
Challenges remain in the development of highly efficient catalysts for selective electrochemical transformation of carbon dioxide (CO 2) to high-valued hydrocarbons. In this study, oxygen vacancy-rich Bi 2O 3 nanosheets coated with polypyrrole (Bi 2O 3@PPy NSs) are designed and synthesized, as precatalysts for selective electrocatalytic CO 2reduction to formate. Systematic material characterization demonstrated that Bi 2O 3@PPy precatalyst can evolve intoBi 2O 2CO 3@PPy nanosheets with rich oxygen vacancies (Bi 2O 2CO 3@PPy NSs) via electrolyte-mediated conversion and function as the real active catalyst for CO 2 reduction reaction electrocatalysis. Coating catalyst with a PPy shell can modulate the interfacial microenvironment of active sites, which work in coordination with rich oxygen vacancies in Bi 2O 2CO 3 and efficiently mediate directional selective CO 2 reduction toward formate formation. With the fine-tuning of interfacial microenvironment, the optimized Bi 2O 3@PPy-2 NSs derived Bi 2O 2CO 3@PPy-2 NSs exhibit a maximum Faradaic efficiency of 95.8% at −0.8 V (versus. reversible hydrogen electrode) for formate production. This work might shed some light on designing advanced catalysts toward selective electrocatalytic CO 2 reduction through local microenvironment engineering. 相似文献
3.
The electrochemical carbon dioxide reduction reaction (E-CO 2RR) to formate is a promising strategy for mitigating greenhouse gas emissions and addressing the global energy crisis. Developing low-cost and environmentally friendly electrocatalysts with high selectivity and industrial current densities for formate production is an ideal but challenging goal in the field of electrocatalysis. Herein, novel titanium-doped bismuth nanosheets (Ti Bi NSs) with enhanced E-CO 2RR performance are synthesized through one-step electrochemical reduction of bismuth titanate (Bi 4Ti 3O 12). We comprehensively evaluated Ti Bi NSs using in situ Raman spectra, finite element method, and density functional theory. The results indicate that the ultrathin nanosheet structure of Ti Bi NSs can accelerate mass transfer, while the electron-rich properties can accelerate the production of *CO 2− and enhance the adsorption strength of *OCHO intermediate. The Ti Bi NSs deliver a high formate Faradaic efficiency (FE formate) of 96.3% and a formate production rate of 4032 µmol h −1 cm −2 at −1.01 V versus RHE. An ultra-high current density of −338.3 mA cm −2 is achieved at −1.25 versus RHE, and simultaneously FE formate still reaches more than 90%. Furthermore, the rechargeable Zn–CO 2 battery using Ti Bi NSs as a cathode catalyst achieves a maximum power density of 1.05 mW cm −2 and excellent charging/discharging stability of 27 h. 相似文献
4.
Electrocatalytic CO 2 reduction reaction (CO 2RR) toward formate production can be operated under mild conditions with high energy conversion efficiency while migrating the greenhouse effect. Herein, an integrated 3D open network of interconnected bismuthene arrays (3D Bi-ene-A/CM) is fabricated via in situ electrochemically topotactic transformation from BiOCOOH nanosheet arrays supported on the copper mesh. The resulted 3D Bi-ene-A/CM consists of 2D atomically thin metallic bismuthene (Bi-ene) in the form of an integrated array superstructure with a 3D interconnected and open network, which harvests the multiple structural advantages of both metallenes and self-supported electrodes for electrocatalysis. Such distinctive superstructure affords the maximized quantity and availability of the active sites with high intrinsic activity and superior charge and mass transfer capability, endowing the catalyst with good CO 2RR performance for stable formate production with high Faradaic efficiency (≈90%) and current density (>300 mA cm ?2). Theoretical calculation verifies the superior intermediate stabilization of the dominant Bi plane during CO 2RR. Moreover, by further coupling anodic methanol oxidation reaction, an exotic electrolytic system enables highly energy-efficient and value-added pair-electrosynthesis for concurrent formate production at both electrodes, achieving substantially improved electrochemical and economic efficiency and revealing the feasibility for practical implementation. 相似文献
5.
Electrochemical CO 2 reduction reaction (CO 2RR) to value-added chemicals/fuels is an effective strategy to achieve the carbon neutral. Palladium is the only metal to selectively produce formate via CO 2RR at near-zero potentials. To reduce cost and improve activity, the high-dispersive Pd nanoparticles on hierarchical N-doped carbon nanocages (Pd/hNCNCs) are constructed by regulating pH in microwave-assisted ethylene glycol reduction. The optimal catalyst exhibits high formate Faradaic efficiency of >95% within −0.05–0.30 V and delivers an ultrahigh formate partial current density of 10.3 mA cm −2 at the low potential of −0.25 V. The high performance of Pd/hNCNCs is attributed to the small size of uniform Pd nanoparticles, the optimized intermediates adsorption/desorption on modified Pd by N-doped support, and the promoted mass/charge transfer kinetics arising from the hierarchical structure of hNCNCs. This study sheds light on the rational design of high-efficient electrocatalysts for advanced energy conversion. 相似文献
6.
Post-combustion flue gas (mainly containing 5–40% CO 2 balanced by N 2) accounts for about 60% global CO 2 emission. Rational conversion of flue gas into value-added chemicals is still a formidable challenge. Herein, this work reports a β-Bi 2O 3-derived bismuth (OD-Bi) catalyst with surface coordinated oxygen for efficient electroreduction of pure CO 2, N 2, and flue gas. During pure CO 2 electroreduction, the maximum Faradaic efficiency (FE) of formate reaches 98.0% and stays above 90% in a broad potential of 600 mV with a long-term stability of 50 h. Additionally, OD-Bi achieves an ammonia (NH 3) FE of 18.53% and yield rate of 11.5 µg h −1 mg cat−1 in pure N 2 atmosphere. Noticeably, in simulated flue gas (15% CO 2 balanced by N 2 with trace impurities), a maximum formate FE of 97.3% is delivered within a flow cell, meanwhile above 90% formate FEs are obtained in a wide potential range of 700 mV. In-situ Raman combined with theory calculations reveals that the surface coordinated oxygen species in OD-Bi can drastically activate CO 2 and N 2 molecules by selectively favors the adsorption of *OCHO and *NNH intermediates, respectively. This work provides a surface oxygen modulation strategy to develop efficient bismuth-based electrocatalysts for directly reducing commercially relevant flue gas into valuable chemicals. 相似文献
7.
Using CO 2, water, and sunlight to produce solar fuel is a very attractive process, which can synchronously reduce carbon and convert solar energy into hydrocarbons. However, photocatalytic CO 2 reduction is often limited by the low selectivity of reduction products and poor photocatalytic activity. In this study, S-scheme Bi 5O 7I-OVs/Cd 0.5Zn 0.5S (Bi 5O 7I-OVs/CZS-0.5) heterojunction with strong interfacial electric field (IEF) is prepared by in situ growth method. The performance of reduction CO 2 to CO is studied by continuous flow photothermal catalytic (PTC) CO 2 reduction platform. 12.5% Bi 5O 7I-OVs/CZS-0.5 shows excellent CO yield of 58.6 µmol g −1 h −1 and selectivity of 98.4%, which are 35.1 times than that of CZS-0.5 under visible light. The charge transfer path of the S-scheme through theoretical calculation (DFT), in situ irradiation Kelvin probe force microscope (ISI-KPFM) and in situ irradiation X-ray photoelectron spectroscopy (ISI-XPS) analysis, is verified. The study can provide useful guidance and reference for improving activity by oxygen vacancy induced strong IEF and the development of a continuous flow PTC CO 2 reduction system. 相似文献
8.
Formic acid is receiving intensive attention as being one of the most progressive chemical fuels for the electrochemical reduction of carbon dioxide. However, the majority of catalysts suffer from low current density and Faraday efficiency. To this end, an efficient catalyst of In/Bi-750 with InO x nanodots load is prepared on a two-dimensional nanoflake Bi 2O 2CO 3 substrate, which increases the adsorption of *CO 2 due to the synergistic interaction between the bimetals and the exposure of sufficient active sites. In the H-type electrolytic cell, the formate Faraday efficiency (FE) reaches 97.17% at –1.0 V (vs reversible hydrogen electrode (RHE)) with no significant decay over 48 h. A formate Faraday efficiency of 90.83% is also obtained in the flow cell at a higher current density of 200 mA cm −2. Both in-situ Fourier transform infrared spectroscopy (FT-IR) and theoretical calculations show that the BiIn bimetallic site can deliver superior binding energy to the *OCHO intermediate, thereby fundamentally accelerating the conversion of CO 2 to HCOOH. Furthermore, assembled Zn-CO 2 cell exhibits a maximum power of 6.97 mW cm −1 and a stability of 60 h. 相似文献
9.
The electroreduction of small molecules to high value-added chemicals is considered as a promising way toward the capture and utilization of atmospheric small molecules. Discovering cheap and efficient electrocatalysts with simultaneously high activity, selectivity, durability, and even universality is desirable yet challenging. Herein, it is demonstrated that Bi 2Te 3 nanoplates (NPs), cheap and noble-metal-free electrocatalysts, can be adopted as highly universal and robust electrocatalysts, which can efficiently reduce small molecules (O 2, CO 2, and N 2) into targeted products simultaneously. They can achieve excellent activity, selectivity and durability for the oxygen reduction reaction with almost 100% H 2O 2 selectivity, the CO 2 reduction reaction with up to 90% Faradaic efficiency (FE) of HCOOH, and the nitrogen reduction reaction with 7.9% FE of NH 3. After electrochemical activation, an obvious Te dissolution happens on the Bi 2Te 3 NPs, creating lots of Te vacancies in the activated Bi 2Te 3 NPs. Theoretical calculations reveal that the Te vacancies can modulate the electronic structures of Bi and Te. Such a highly electroactive surface with a strong preference in supplying electrons for the universal reduction reactions improves the electrocatalytic performance of Bi 2Te 3. The work demonstrates a new class of cheap and versatile catalysts for the electrochemical reduction of small molecules with potential practical applications. 相似文献
10.
Narrow-bandgap semiconductors are promising photocatalysts facing the challenges of low photoredox potentials and high carrier recombination. Here, a broken-gap heterojunction Bi/Bi 2S 3/Bi/MnO 2/MnO x, composed of narrow-bandgap semiconductors, is selectively decorated by Bi, MnO x nanodots (NDs) to achieve robust photoredox ability. The Bi NDs insertion at the Bi 2S 3/MnO 2 interface induces a vertical carrier migration to realize sufficient photoredox potentials to produce O 2•− and •OH active species. The surface decoration of Bi 2S 3/Bi/MnO 2 by Bi and MnO x cocatalysts drives electrons and holes in opposite directions for optimal photogenerated charge separation. The selective cocatalysts decoration realizes synergistic surface and bulk phase carrier separation. Density functional theory (DFT) calculation suggests that Bi and MnOx NDs act as active sites enhancing the absorption and reactants activation. The decorated broken-gap heterojunction demonstrates excellent performance for full-light driving organic pollution degradation with great commercial application potential. 相似文献
11.
It is a substantial challenge to construct electrocatalysts with high activity, good selectivity, and long-term stability for electrocatalytic reduction of carbon dioxide to formic acid. Herein, bismuth and indium species are innovatively integrated into a uniform heterogeneous spherical structure by a neoteric quasi-microemulsion method, and a novel C@In 2O 3@Bi 50 core-shell structure is constructed through a subsequent one-step phase separation strategy due to melting point difference and Kirkendall effect with the nano-limiting effect of the carbon structure. This core-shell C@In 2O 3@Bi 50 catalyst can selectively reduce CO 2 to formate with high selectivity (≈90% faradaic efficiency), large partial current density (24.53 mA cm −2 at −1.36 V), and long-term stability (up to 14.5 h), superior to most of the Bi-based catalysts. The hybrid Bi/In 2O 3 interfaces of core-shell C@In 2O 3@Bi will stabilize the key intermediate HCOO* and suppress CO poisoning, benefiting the CO 2RR selectivity and stability, while the internal cavity of core-shell structure will improve the reaction kinetics because of the large specific surface area and the enhancement of ion shuttle and electron transfer. Furthermore, the nano-limited domain effect of outmost carbon prevent active components from oxidation and agglomeration, helpful for stabilizing the catalyst. This work offers valuable insights into core-shell structure engineering to promote practical CO 2 conversion technology. 相似文献
12.
A series of Bi 2S 3/(BiO) 2CO 3 composite photocatalysts with different loadings of amorphous Bi 2S 3 were successfully synthesized through an ultrasonic-assisted ion-exchange reaction between thioacetamide (CH 3CSNH 2) and (BiO) 2CO 3, and characterized by XRD, XPS, BET, EELS, EDX, SEM, TEM/HRTEM, UV–Vis, and photoluminescence (PL) techniques. The results of TEM/HRTEM, EELS, and EDX indicate that the composite catalyst Bi 2S 3/(BiO) 2CO 3 has been successfully synthesized with the deposited Bi 2S 3 present in amorphous state on the surface of (BiO) 2CO 3. The activities of the catalysts for RhB degradation under visible light show that the catalyst prepared under ultrasonic is more active than the one synthesized without ultrasonic. The optimized sample Bi 2S 3/(BiO) 2CO 3 (U5.0) exhibits a much higher activity, about 4.8 times to that of pure (BiO) 2CO 3. Based upon the band structures of Bi 2S 3/(BiO) 2CO 3, it is deduced that the migration of the visible light-induced electrons from the conduction band of Bi 2S 3 to that of (BiO) 2CO 3 should have facilitated the separation of photogenerated carriers, as confirmed by the suppressed photoluminescence spectra. Using different scavengers, the ·O 2 ? and holes are clearly identified as the main oxidative species for RhB photodegradation. In light of these observations, a potential photocatalytic mechanism of RhB degradation over Bi 2S 3/(BiO) 2CO 3 is proposed. 相似文献
13.
Bi12O17Cl2 is an ideal photocatalytic material with an appropriate band gap and visible light absorption. However, the performance of a single Bi12O17Cl2 photocatalytic material is still limited by the low separation rate of photogenerated electrons and holes. In this paper, the 2D Bi12O17Cl2 and 2D g-C3N4 materials were prepared, and fabricated 2D/2D Bi12O17Cl2/g-C3N4 nanosheets by electrostatic self-assembly using the different surface electrical properties of the two materials. The formation of an electric interface field between Bi12O17Cl2 and g-C3N4 nanosheets and the matched energy band structure of the two materials can effectively promote the separation of electrons and holes and reduce recombination to improve the photocatalytic performance of semiconductor materials. The Bi12O17Cl2/g-C3N4 with appropriate composite ratio has good degradation activity of Rhodamine-B (RhB) organic pollutants. The composite material can degrade nearly 100% of 10 ppm RhB in the reaction time of 2 h under neutral conditions and completely degrade rhodamine B in 90 min under acidic conditions. 相似文献
14.
The field of photovoltaics is revolutionized in recent years by the development of two–dimensional (2D) type-II heterostructures. These heterostructures are made up of two different materials with different electronic properties, which allows for the capture of a broader spectrum of solar energy than traditional photovoltaic devices. In this study, the potential of vanadium (V)-doped WS 2 is investigated, hereafter labeled V-WS 2, in combination with air-stable Bi 2O 2Se for use in high-performance photovoltaic devices. Various techniques are used to confirm the charge transfer of these heterostructures, including photoluminescence (PL) and Raman spectroscopy, along with Kelvin probe force microscopy (KPFM). The results show that the PL is quenched by 40%, 95%, and 97% for WS 2/Bi 2O 2Se, 0.4 at.% V-WS 2/Bi 2O 2Se, and 2 at.% V-WS 2/Bi 2O 2Se, respectively, indicating a superior charge transfer in V-WS 2/Bi 2O 2Se compared to pristine WS 2/Bi 2O 2Se. The exciton binding energies for WS 2/Bi 2O 2Se, 0.4 at.% V-WS 2/Bi 2O 2Se and 2 at.% V-WS 2/Bi 2O 2Se heterostructures are estimated to be ≈130, 100, and 80 meV, respectively, which is much lower than that for monolayer WS 2. These findings confirm that by incorporating V-doped WS 2, charge transfer in WS 2/Bi 2O 2Se heterostructures can be tuned, providing a novel light-harvesting technique for the development of the next generation of photovoltaic devices based on V-doped transition metal dichalcogenides (TMDCs)/Bi 2O 2Se. 相似文献
15.
Expedition of electron transfer efficiency and optimization of surface reactant adsorption products desorption processes are two main challenges for developing non‐noble catalysts in the oxygen reduction reaction (ORR) and CO 2 reduction reaction (CRR). A heterojunction prototype on Co 3S 4@Co 3O 4 core–shell octahedron structure is established via hydrothermal lattice anion exchange protocol to implement the electroreduction of oxygen and carbon dioxide with high performance. The synergistic bifunctional catalyst consists of p‐type Co 3O 4 core and n‐type Co 3S 4 shell, which afford high surface electron density along with high capacitance without sacrificing mechanical robustness. A four electron ORR process, identical to the Pt catalyzed ORR, is validated using the core–shell octahedron catalyst. The synergistic interaction between cobalt sulfide and cobalt oxide bicatalyst reduces the activation energy to convert CO 2 into adsorbed intermediates and hereby enables CRR to run at a low overpotential, with formate as the highly selective main product at a high faraday efficiency of 85.3%. The remarkable performance can be ascribed to the synergistic coupling effect of the structured co‐catalysts; heterojunction structure expedites the electron transfer efficiency and optimizes surface reactant adsorption product desorption processes, which also provide theoretical and pragmatic guideline for catalyst development and mechanism explorations. 相似文献
16.
Heterostructured Fe 3O 4/Bi 2O 2CO 3 photocatalyst was synthesized by a two-step method. First, Fe 3O 4 nanoparticles with the size of ca. 10 nm were synthesized by chemical method at room temperature and then heterostructured Fe 3O 4/Bi 2O 2CO 3 photocatalyst was synthesized by hydrothermal method at 180 °C for 24 h with the addition of 10 wt% Fe 3O 4 nanoparticles into the precursor suspension of Bi 2O 2CO 3. The pH value of synthesis suspension was adjusted to 4 and 6 with the addition of 2 M NaOH aqueous solution. By controlling the pH of synthesis suspension at 4 and 6, sphere- and flower-like Fe 3O 4/Bi 2O 2CO 3 photocatalysts were obtained, respectively. Both photocatalysts demonstrate superparamagnetic behavior at room temperature. The UV–vis diffuse reflectance spectra of the photocatalysts confirm that all the heterostructured photocatalysts are responsive to visible light. The photocatalytic activity of the heterostructured photocatalysts was evaluated for the degradation of methylene blue (MB) and methyl orange (MO) in aqueous solution over the photocatalysts under visible light irradiation. The heterostructured photocatalysts prepared in this study exhibit highly efficient visible-light-driven photocatalytic activity for the degradation of MB and MO, and they can be easily recovered by applying an external magnetic field. 相似文献
17.
Bi_2O_2CO_3是一种Bi类半导体催化剂,文章研究了它的超声催化性能。首先,采用水热法制备了微球型的Bi_2O_2CO_3,利用X射线衍射(X-ray Diffraction, XRD)、扫描电子显微镜(Scanning Electron Microscope, SEM)、紫外-可见漫反射光谱对样品的晶体结构、微观形貌、光学特性进行了表征。然后,以罗丹明B(Rh B)作为模型污染物,通过研究超声催化降解罗丹明B来评测Bi_2O_2CO_3的超声催化性能。研究了催化剂的浓度(Ccatalytic)、初始罗丹明B染料的浓度(CRhB)和超声功率(P)等实验因素对超声催化降解效率的影响。得出在Ccatalytic=3 g·L-1,CRhB=10 mg·L-1和P=400 W条件下降解罗丹明B的效率最高,其最高降解效率可以达到91.7%。 相似文献
18.
Hierarchical β-Bi 2O 3/Bi 2MoO 6 heterostructured flower-like microspheres assembled from nanoplates with different β-Bi 2O 3 loadings (0–26.5 mol%) were synthesized through a one-step template-free solvothermal route. Under visible-light illumination ( λ > 420 nm), over 99% of rhodamine B was degraded within 90 min on the 21.9 mol% of β-Bi 2O 3 loading Bi 2O 3/Bi 2MoO 6 microspheres. The remarkable enhancement of photocatalytic activity of the hierarchical Bi 2O 3/Bi 2MoO 6 micro/nanostructures can be attributed to the effective separation of the photoinduced charge carriers at the interfaces and in the semiconductors. The electrons (e −) are the main active species in aqueous solution under visible-light irradiation. The Bi 2O 3/Bi 2MoO 6 also displays visible-light photocatalytic activity for the destruction of E. coli. In addition, the β-Bi 2O 3 in the hierarchical Bi 2O 3/Bi 2MoO 6 microspheres is very stable and the composite can be easily recycled by a simple filtration step, thus the second pollution can be effectively avoided. A possible photocatalytic mechanism was proposed based on the experimental results. 相似文献
19.
Photodynamic therapy (PDT) efficacy has been severely limited by oxygen (O 2) deficiency in tumors and the electron–hole separation inefficiency in photosensitizers, especially the long-range diffusion of O 2 toward photosensitizers during the PDT process. Herein, novel bismuth sulfide (Bi 2S 3)@bismuth (Bi) Z-scheme heterostructured nanorods (NRs) are designed to realize the spatiotemporally synchronous O 2 self-supply and production of reactive oxygen species for hypoxic tumor therapy. Both narrow-bandgap Bi 2S 3 and Bi components can be excited by a near-infrared laser to generate abundant electrons and holes. The Z-scheme heterostructure endows Bi 2S 3@Bi NRs with an efficient electron–hole separation ability and potent redox potentials, where the hole on the valence band of Bi 2S 3 can react with water to supply O 2 for the electron on the conduction band of Bi to produce reactive oxygen species. The Bi 2S 3@Bi NRs overcome the major obstacles of conventional photosensitizers during the PDT process and exhibit a promising phototherapeutic effect, supplying a new strategy for hypoxic tumor elimination. 相似文献
20.
Electrochemical CO 2 reduction reaction (CO 2RR) is a promising strategy for waste CO 2 utilization and intermittent electricity storage. Herein, it is reported that bimetallic Cu/Pd catalysts with enhanced *CO affinity show a promoted CO 2RR performance for multi-carbon (C2+) production under industry-relevant high current density. Especially, bimetallic Cu/Pd-1% catalyst shows an outstanding CO 2-to-C2+ conversion with 66.2% in Faradaic efficiency (FE) and 463.2 mA cm −2 in partial current density. An increment in the FE ratios of C2+ products to CO for Cu/Pd-1% catalyst further illuminates a preferable C2+ production. In situ Raman spectra reveal that the atop-bounded CO is dominated by low-frequency band CO on Cu/Pd-1% that leads to C2+ products on bimetallic catalysts, in contrast to the majority of high-frequency band CO on Cu that favors the formation of CO. Density function theory calculation confirms that bimetallic Cu/Pd catalyst enhances the *CO adsorption and reduces the Gibbs free energy of the C C coupling process, thereby favoring the formation of C2+ products. 相似文献
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