Kinetics Of Catalytic Reactions Research Articles

Effects of silanol defects and Ti site location within Ti-MWW on alkene epoxidation with aqueous hydrogen peroxide

Catalytic reaction kinetics and thermodynamics within zeolites respond to the physical properties of the framework through noncovalent interactions with solvents. Here, we demonstrate that rates of alkene epoxidations depend sensitively upon the topological location of Ti atoms and the density of silanol ((SiOH)x) defects in hydrothermally synthesized Ti-MWW catalysts. Turnover rates for 1-hexene epoxidation do not change systematically with (SiOH)x density unlike previous reports for other zeolite framework. Site-averaged turnover rates on Ti-MWW catalysts with the greatest portion of Ti sites located in sinusoidal channels exceed those on materials with most Ti in supercages by a factor of 40-fold. These differences appear to reflect free energy contributions and compensation between activation enthalpies and entropies, induced by the structural organization of solvent molecules that responds differently to the topological locations of active sites and the presence of defects.

Green synthesis of iron nanoparticles from the baru (Dipteryx alata) endocarp extract for the efficient removal of rhodamine B and caffeine from water through the heterogeneous Fenton process

Abstract This study presents the first-time synthesis of iron nanoparticles (FeNPs) using an aqueous extract from the baru fruit endocarp (Dipteryx alata). Characterization through scanning electron microscopy and dynamic light scattering revealed spherical shapes with an average diameter of 419.2 nm. Fourier transform infrared spectroscopy identified phytochemicals from the baru fruit extract, acting as both reducing and stabilizing agents. X-ray diffraction confirmed the amorphous nature of the FeNPs. The Fenton-like catalytic efficiency of FeNPs was investigated for degrading rhodamine B (RhB) and caffeine. The impact of crucial parameters such as pH, H2O2 dosage, nanoparticles concentration, and temperature on the degradation process was assessed. At pH 3.0, with 1.0 g L−1 of FeNPs, 1% H2O2, and 45 °C, RhB and caffeine degradation reached 99.14 and 92.01%, respectively. The catalytic reaction kinetics followed a pseudo-first-order model for caffeine and a pseudo-second-order model for RhB. Phytotoxicity studies on Cucumis sativus confirmed the non-toxic nature of the degraded products of RhB and caffeine. These findings highlight the potential of FeNPs synthesized from the baru endocarp extract as a catalyst for removing organic pollutants, suggesting promising applications in environmental remediation and related fields.

Unlocking the Mysteries of Technical Catalyst Deactivation: A View from Space

AbstractModern analytical techniques enable researchers to study heterogeneous catalytic systems at extended length scales and with local probing methods which were previously impractical. Such spatially–resolved analyses are ideal for exploring the complex dynamics governing catalytic activity, and more specifically, deactivation. Here we highlight significant experimental concepts and milestones in the spatially–resolved analysis of technical catalysts, where it is now possible to study catalyst behavior even up to industrially relevant scale. At such extended length scales and in contrast to many model systems, spatial heterogeneities in solid catalyst bodies may play a crucial role in controlling catalytic properties and may be closely linked to catalyst deactivation. Spatially–resolved studies can therefore provide a unique source of information about such local phenomena. Researchers can gain a deeper insight into the operational life of a catalyst by understanding deactivation patterns, which are one of many factors influencing the dynamics of catalytic reactions. In turn, this information promotes the design of more robust and sustainable catalytic systems. We therefore outline the current state of spatially–resolved characterization, together with its role in deconvoluting the complexity of technical catalysts and their deactivation.

Application of the kinetic polynomial idea to describe catalytic hydrogenation of propene

AbstractThe kinetics of heterogeneous catalytic reactions is a topic of theoretical and practical importance that combines theoretical and experimental efforts to achieve a deeper insight into the process. Theoretical aspects are concerned with determination of the process mechanism, whereas in practical applications kinetic experiments are applied to assist reactor design and scaling up of various processes. These approaches overlap; basis of the assumed mechanism that consists of many elementary steps, it is possible to find a kinetic equation for which precision is verified by comparison with experimental data. The method most often applied requires finding a single step that has the strongest influence on the process rate. This “classical approach” fails if the rate of two or more steps has comparable values, the precision of the determined kinetic rate becomes only average or even low. Such accuracy was observed, among others, for the gas‐phase hydrogenation of propene. The reaction is easy to carry out and proceeds under mild conditions; the byproducts are not observed. It suggests that there cannot be a single dominating effect step on the process rate. In this work, the application of the polynomial kinetic idea to the gas‐phase hydrogenation of the propene process realized in practice is tested. An attempt of obtaining a handy and precise relationship, without insignificant parameters was made. To realize this, the theoretical form of the polynomial kinetic was derived, and then, using statistical analysis of estimated polynomial parameters, the kinetic relationship was simplified. The final version of the kinetic polynomial and some selected kinetic equations taken from the literature were compared with respect to precision. The differences were significant: the precision of anticipation of the kinetic rate by the polynomial kinetic was 5% higher than for the power law and 12% higher than for the LHHW kinetic.

Application of SO42–/Fe2O3-CuO solid superacid materials in cyclic compounds from wastewater: Performance and mechanism

In wastewater treatment, the degradation of refractory cyclic compounds by catalytic ozonation using sulfated solid superacid has not been thoroughly investigated. The doped S element alters the electronic activity and drives the ozone oxidation of recalcitrant organic pollutants, potentially leading to an increase in catalytic efficiency. This study aimed to develop a novel iron-copper sulfate (SO42–/Fe2O3-CuO) solid superacid composite to strengthen catalytic reactions. According to the characterization results, the embedding of SO42– enhanced the electron transfer inside the material, leading to more Lewis acid sites, which facilitated the catalytic decomposition of O3. The catalytic degradation and reaction kinetics experiments on quinoline verified the superior catalytic performance of the SO42–/Fe2O3-CuO system compared to other systems. Fluorescence, UV–Vis spectrophotometry, and EPR experiments demonstrated that the hydroxyl radicals (OH), superoxide radicals (O2−), and singlet oxygen (1O2) were generated in the SO42–/Fe2O3-CuO system, and their presence accelerated the redox cycling of Fe(III)/Fe(II) and Cu(II)/Cu(I). In addition, the possible degradation pathways of quinoline were verified by density functional theory (DFT) calculations, and the toxicity of intermediates was assessed by quantitative structure–activity relationship (QSAR) analysis. Finally, the applicability of the SO42–/Fe2O3-CuO catalytic system in bio-treated coking wastewater (BTCW) was validated. GC–MS experiments further confirmed that it was mainly the cyclic compounds that contributed to the removal rate during the catalytic process. In summary, this study demonstrated the significant potential of the SO42–/Fe2O3-CuO catalytic system in degrading refractory cyclic compounds, providing valuable technical support for the field of wastewater treatment.

Defect Anchoring [S–Ni–P] Interfacial Channel Regulating Charge Migration for Efficient Photoelectrochemical Water Splitting

AbstractRegulating bulk charge carrier transfer and surface catalytic reaction kinetics is thought a big challenge to photoelectrochemical (PEC) water splitting. Herein, the dual sites of CoNiP are delicately introduced into ZnIn2S4 (RZIS‐CoNiP) nanosheet arrays via a defect anchoring method. The paving [S─Ni─P] interfacial bond like a “bridge” can greatly reduce the phase resistance, improve the charge separation and migration, and promote the surface oxygen evolution reaction (OER) reaction. As expected, the optimized RZIS‐CoNiP photoanode achieved a maximum photocurrent density of 4.77 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE) in neutral electrolyte solution without the presence of any sacrificial agents, which is ≈12 times higher than that of the pristine ZnIn2S4 under AM 1.5G illumination. And the amount of oxygen evolution for the RZIS‐CoNiP photoanode is as high as 21.9 µmol in 3 h. Transient spectroscopy measurements and density functional theory (DFT) calculations in situ discovered the mechanism of defect anchoring [S─Ni─P] bond on regulating charge transfer and surface reaction processes. This work provides a feasible anchoring interface route through defect engineering to regulate charge carrier transfer for PEC water splitting.

Cactus-like NC/CoxP electrode enables efficient and stable hydrogen evolution for saline water splitting

Designing efficient and robust catalysts for hydrogen evolution reaction (HER) is imperative for saline water electrolysis technology. A catalyst composed of CoxP nanowires array with N-doped carbon nanosheets (NC) was fabricated on Ni foam (NF) by an in-situ growth strategy. The material is designated as NC/CoxP@NF. In the preparation process, Co(OH)2 nanowires were transformed into a metal organic framework of cobalt (ZIF-67) on NF by the dissolution-coordination of endogenous Co2+ and 2-methylimidazole. The resulting cactus-like microstructure gives NC/CoxP@NF abundant exposed active sites and ion transport channels, which improve the HER catalytic reaction kinetics. Furthermore, the interconnected alternating nanowires and free-standing nanosheets in NC/CoxP@NF improve its structural stability, and the formation of surface polyanions (phosphate) and a NC nanosheet protective layer improve the anti-corrosive properties of catalysts. Thus, the NC/CoxP@NF has an excellent performance, requiring overpotentials of 107 and 133 mV for HER to achieve 10 mA cm−2 in 1.0 mol L−1 KOH and 1.0 mol L−1 KOH + 0.5 mol L−1 NaCl, respectively. This in-situ transformation strategy is a new way of constructing highly-efficient HER catalysts for saline water electrolysis.

Tuning Morphology and Electronic Structure of Cobalt Metaphosphate Via Vanadium‐Doping for Efficient Water and Urea Splitting

AbstractDesigning efficient multifunctional electrocatalysts for water and urea splitting to produce green hydrogen presents a significant yet worthwhile challenge. Herein, the morphology and electronic structure of cobalt metaphosphate (Co2P4O12) by vanadium (V) doping, resulting in improved electrocatalytic activity and stability for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) are simultaneously regulated. Theory calculations show that V‐doped Co2P4O12 (V‐Co2P4O12) can boost the kinetics of catalytic reactions by optimizing the d‐band center of Co atoms and the binding strength of intermediates, as well as enhancing the density of states. Moreover, the doping of V into Co2P4O12 crystalline structure benefits the formation of a thicker amorphous layer during the catalytic process, which could enhance its alkaline corrosion resistance and stability. Additionally, the multilevel nanostructures of V‐Co2P4O12 provide rich active sites for catalytic reactions. As a result, a two‐electrode electrolyzer assembled by V‐doped Co2P4O12 delivers low voltages for overall water and urea splitting. The superior performance suggests that the proposed V‐doping strategy is a promising way to regulate electrocatalytic activity for catering to green electrocatalytic applications.

Surface reconstruction in amorphous CoFe-based hydroxides/crystalline phosphide heterostructure for accelerated saline water electrolysis

Developing electrocatalysts with high activity and robust performance for large-scale seawater electrolysis to produce hydrogen holds immense significance. Herein, a highly active bifunctional electrode composed of amorphous cobalt-iron layered double hydroxides (CoFeLDH) and crystalline nickel phosphide (Ni2P) (denoted as CoFeLDH@Ni2P), is employed to boost hydrogen production through seawater electrolysis. The strong interface coupling effectively modifies the electronic structure at active sites, thereby accelerating the catalytic reaction kinetics. Impressively, in situ Raman and post-stability analyses demonstrate a unique reconstruction behavior on the CoFeLDH@Ni2P electrode. Bimetal co-incorporated NiOOH (CoFe-NiOOH) and Ni(OH)2 species are formed during the oxygen evolution reaction (OER), while CoFeLDH@Ni2P can transform into Ni(OH)2 species during the hydrogen evolution reaction (HER) process. Furthermore, the highly negatively charged surface selectively rejects Cl− ions by formed PO43−, endowing CoFeLDH@Ni2P with excellent tolerance and promising durability in saline electrolytes. Consequently, the CoFeLDH@Ni2P electrode exhibits an overpotential of 106 mV for HER at 10 mA cm−2 and 308 mV for OER to achieve 100 mA cm−2 in 1.0 M KOH solution. Additionally, the CoFeLDH@Ni2P(+,-) electrolyzer requires a low cell voltage of 1.56 V to deliver 10 mA cm−2 in 1.0 M KOH + Seasalt. This work presents an appealing strategy for the rational design of advanced electrocatalysts with amorphous-crystalline interfaces, which reveals the source of the activity of transition-metal phosphating compounds in saline water electrolysis.

In Situ Infrared Spectroscopic Evidence of Enhanced Electrochemical CO2 Reduction and C-C Coupling on Oxide-Derived Copper.

The reaction mechanism of CO2 electroreduction on oxide-derived copper has not yet been unraveled even though high C2+ Faradaic efficiencies are commonly observed on these surfaces. In this study, we aim to explore the effects of copper anodization on the adsorption of various CO2RR intermediates using in situ surface-enhanced infrared absorption spectroscopy (SEIRAS) on metallic and mildly anodized copper thin films. The in situ SEIRAS results show that the preoxidation process can significantly improve the overall CO2 reduction activity by (1) enhancing CO2 activation, (2) increasing CO uptake, and (3) promoting C-C coupling. First, the strong *COO- redshift indicates that the preoxidation process significantly enhances the first elementary step of CO2 adsorption and activation. The rapid uptake of adsorbed *COatop also illustrates how a high *CO coverage can be achieved in oxide-derived copper electrocatalysts. Finally, for the first time, we observed the formation of the *COCHO dimer on the anodized copper thin film. Using DFT calculations, we show how the presence of subsurface oxygen within the Cu lattice can improve the thermodynamics of C2 product formation via the coupling of adsorbed *CO and *CHO intermediates. This study advances our understanding of the role of surface and subsurface conditions in improving the catalytic reaction kinetics and product selectivity of CO2 reduction.

Nickel Nanoparticles Protruding from Molybdenum Carbide Micropillars with Carbon Layer-Protected Biphasic 0D/1D Heterostructures for Efficient Water Splitting.

It remains a tremendous challenge to achieve high-efficiency bifunctional electrocatalysts for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) for hydrogen production by water splitting. Herein, a novel hybrid of 0D nickel nanoparticles dispersed on the one-dimensional (1D) molybdenum carbide micropillars embedded in the carbon layers (Ni/Mo2C@C) was successfully prepared on nickel foam by a facile pyrolysis strategy. During the synthesis process, the nickel nanoparticles and molybdenum carbide were simultaneously generated under H2 and C2H2 mixed atmospheres and conformally encapsulated in the carbon layers. Benefiting from the distinctive 0D/1D heterostructure and the synergistic effect of the biphasic Mo2C and Ni together with the protective effect of the carbon layer, the reduced activation energy barriers and fast catalytic reaction kinetics can be achieved, resulting in a small overpotential of 96 mV for the HER and 266 mV for the OER at the current density of 10 mA cm-2 together with excellent durability in 1.0 M KOH electrolyte. In addition, using the developed Ni/Mo2C@C as both the cathode and anode, the constructed electrolyzer exhibits a small voltage of 1.55 V for the overall water splitting. The novel designed Ni/Mo2C@C may give inspiration for the development of efficient bifunctional catalysts with low-cost transition metal elements for water splitting.

Time-resolved surface reaction kinetics in the pressure gap.

We extend the use of our recently developed Near-Ambient Pressure Velocity Map Imaging (NAP-VMI) technique to study the kinetics and dynamics of catalytic reactions in the pressure gap. As an example, we show that NAP-VMI combined with molecular beam surface scattering allows the direct measurement of time- and velocity-resolved kinetics of the scattering and oxidation of CO on the Pd(110) surface with oxygen pressures at the surface up to 1 × 10-5 mbar, where different metastable surface structures form. Our results show that the c(2 × 4) oxide structure formed at low O2 pressure is highly active for CO oxidation. The velocity distribution of the CO2 products shows the presence of two reaction channels, which we attribute to reactions starting from two distinct but rapidly interconverting CO binding sites. The effective CO oxidation reaction activation energy is Er = (1.0 ± 0.13) eV. The CO2 production is suppressed at higher O2 pressure due to the number of antiphase domain boundaries increasing, and the missing row sites are filled by O-atoms at O2 pressures approaching 1 × 10-6 mbar. Filling of these sites by O-atoms reduces the CO surface lifetime, meaning the surface oxide is inactive for CO oxidation. We briefly outline further developments planned for the NAP-VMI and its application to other types of experiments.

Dynamic evolution processes in electrocatalysis: structure evolution, characterization and regulation.

Reactions on electrocatalytic interfaces often involve multiple processes, including the diffusion, adsorption, and conversion of reaction species and the interaction between reactants and electrocatalysts. Generally, these processes are constantly changing rather than being in a steady state. Recently, dynamic evolution processes on electrocatalytic interfaces have attracted increasing attention owing to their significant roles in catalytic reaction kinetics. In this review, we aim to provide insights into the dynamic evolution processes in electrocatalysis to emphasize the importance of unsteady-state processes in electrocatalysis. Specifically, the dynamic structure evolution of electrocatalysts, methods for the characterization of the dynamic evolution and the strategies for the regulation of the dynamic evolution for improving electrocatalytic performance are summarized. Finally, the conclusion and outlook on the research on dynamic evolution processes in electrocatalysis are presented. It is hoped that this review will provide a deeper understanding of dynamic evolution in electrocatalysis, and studies of electrocatalytic reaction processes and kinetics on the unsteady-state microscopic spatial and temporal scales will be given more attention.

Catechol‐Isolated Atomically Dispersed Nanocatalysts for Self‐Motivated Cocatalytic Tumor Therapy

AbstractNanocatalytic tumor therapy based on Fenton nanocatalysts has attracted considerable attention because of its therapeutic specificity, enhanced outcomes, and high biocompatibility. Nevertheless, the rate‐determining step in Fenton chemistry, which involves the transition of a high‐valence metallic center (FeIII) to a Fenton‐active low‐valence metallic center (FeII), has hindered advances in nanocatalyst‐based therapeutics. In this study, we constructed mesoporous single iron atomic nanocatalysts (mSAFe NCs) by employing catechols from dopamine to coordinate and isolate single iron atoms. The catechols also serve as reductive ligands, generating a field‐effect‐based cocatalytic system that instantly reduces FeIII species to FeII species within the mSAFe NCs. This self‐motivated cocatalytic strategy enabled by mSAFe NCs accelerates the kinetics of the Fenton catalytic reaction, resulting in remarkable performance for nanocatalytic tumor therapy both in vitro and in vivo.

Catechol-Isolated Atomically Dispersed Nanocatalysts for Self-Motivated Cocatalytic Tumor Therapy.

Nanocatalytic tumor therapy based on Fenton nanocatalysts has attracted considerable attention because of its therapeutic specificity, enhanced outcomes, and high biocompatibility. Nevertheless, the rate-determining step in Fenton chemistry, which involves the transition of a high-valence metallic center (FeIII ) to a Fenton-active low-valence metallic center (FeII ), has hindered advances in nanocatalyst-based therapeutics. In this study, we constructed mesoporous single iron atomic nanocatalysts (mSAFe NCs) by employing catechols from dopamine to coordinate and isolate single iron atoms. The catechols also serve as reductive ligands, generating a field-effect-based cocatalytic system that instantly reduces FeIII species to FeII species within the mSAFe NCs. This self-motivated cocatalytic strategy enabled by mSAFe NCs accelerates the kinetics of the Fenton catalytic reaction, resulting in remarkable performance for nanocatalytic tumor therapy both in vitro and in vivo.

Porous carbon/minerals interwoven particle electrodes co-constructed by residual carbon and ash from coal gasification fine slag and its synergistic electrocatalytic mechanism

Complex distribution forms of carbon/ash in coal gasification fine slag (GFS) make it impossible to separate precisely. A combined alkali fusion-polymerization-hydrothermal process was designed to synthesize porous carbon/minerals interwoven particle electrodes (FSAPH) co-constructed by carbon/ash from GFS for electrooxidation treatment of m-cresol wastewater. Based on the hydrogen bonding and coordination capabilities of polyaniline (PAIN), the deconstructed aluminosilicate was regenerated in sheet-like form dispersedly on carbon matrix, effectively enhancing synergistic behavior of carbon and minerals. The electrochemical assessment exhibited superior properties, including a large voltammetry charge of 9.533 mC/cm3, high oxygen evolution potential of 2.15 V, low charge-transfer resistance of 0.36 Ω, and excellent cycle stability. The three-dimensional electrode filled with 0.15 g FSAPH performed pre-adsorption of m-cresol without electricity. Intraparticle diffusion is mainly controlled by SiOSi/AlOH groups on the mineral surface, and the adsorption rate constant KS1 reached 0.491·min−1. After being electrified, AlOH converted H2O2 via three pathways to generate reactive oxygen species (ROS). The rate-determining step in path 2 was the entry of oxygen atoms in OH into the AlOH lattice with the lowest energy barrier of 1.71 kcal/mol. 79.61 mg/L m-cresol can be rapidly degraded within 24 min, 2.6 times that of the two-dimensional electrode system. The electrostatic attraction of carbon ensured the continuous and rapid supply of H2O2 near mineral active sites due to the carbon/minerals interwoven structure. Extensive catalytic sites in thin sheet-like minerals accelerated the electrooxidation of m-cresol on carbon, boosting the catalytic reaction kinetics. Hence, the study realized the comprehensive utilization of carbon/ash in GFS and waste treatment with waste.

Addressing polar solvent challenges in the heterogenization of palladium catalysed Hayashi-Miyaura reaction on polymer support

The development of recyclable heterogeneous catalysts for the palladium-catalysed additions of arylboronic acids to nitrostyrenes is investigated in this study. Two strategies, direct copolymerization and post-modification, are explored for immobilizing chiral isoquinoline-oxazoline ligands onto polymer matrices. Various copolymer formulations are prepared, and their catalytic activity, recyclability, and reaction kinetics are evaluated. The incorporation of polar functional groups into the polymer matrix enhances catalytic properties, albeit with a decrease in reaction rate compared to the homogeneous system. Post-modification using a polystyrene-polyethylene glycol (PS-PEG) support shows promise, resulting in a moderate decrease in reaction rate and satisfactory performance over multiple reaction cycles. The findings provide valuable insights into the immobilization of chiral ligands and highlight the advantages and limitations of different polymer compositions. These results contribute to the development of advanced catalytic systems for the synthesis of biologically relevant compounds.

Regulation Strategy of Nanostructured Engineering on Indium-Based Materials for Electrocatalytic Conversion of CO2.

Electrochemical carbon dioxide reduction (CO2 RR), as an emerging technology, can combine with sustainable energies to convert CO2 into high value-added products, providing an effective pathway to realize carbon neutrality. However, the high activation energy of CO2 , low mass transfer, and competitive hydrogen evolution reaction (HER) leads to the unsatisfied catalytic activity. Recently, Indium (In)-based materials have attracted significant attention in CO2 RR and a series of regulation strategies of nanostructured engineering are exploited to rationally design various advanced In-based electrocatalysts, which forces the necessary of a comprehensive and fundamental summary, but there is still a scarcity. Herein, this review provides a systematic discussion of the nanostructure engineering of In-based materials for the efficient electrocatalytic conversion of CO2 to fuels. These efficient regulation strategies including morphology, size, composition, defects, surface modification, interfacial structure, alloying, and single-atom structure, are summarized for exploring the internal relationship between the CO2 RR performance and the physicochemical properties of In-based catalysts. The correlation of electronic structure and adsorption behavior of reaction intermediates are highlighted to gain in-depth understanding of catalytic reaction kinetics for CO2 RR. Moreover, the challenges and opportunities of In-based materials are proposed, which is expected to inspire the development of other effective catalysts for CO2 RR.

Carbothermal shock synthesis of CoO/N/C nanoparticles with superior durability for oxygen reduction reaction

Designing an efficient and stable non-precious metal cathode catalyst is essential to reduce fuel cell cost and promote fuel cell commercialization. Herein, ZIF-67 and carbon powder are rapidly heated using a transient Joule heat device to pyrolyze ZIF-67 to form a CoO/N/C nanocatalysts. The prepared CoO/N/C-90 is comprised of 3–4 nm CoO nanoparticles loaded on a carbon substrate. In alkaline medium the Tafel slope of CoO/N/C-90 is 50 mV dec−1, and a half-wave potential (E1/2) of 0.82 V towards oxygen reduction reaction (ORR). The E1/2 only experiences a negative shift of 4 mV after 40,000 cyclic voltammetry (CV) cycles, demonstrating excellent catalytic reaction kinetics and durability. The CoO/N/C-90 is assembled into direct borohydride fuel cells (DBFC) as a cathode, achieving a maximum power density (Pmax) of 526 mW cm−2 at 60 °C. This work indicates that the CoO/N/C-90 is an efficient and stable non-precious metal catalyst for DBFCs.

Electrodeposition synthesis of cobalt-molybdenum bimetallic phosphide on nickel foam for efficient water splitting

A reasonable design of excellent bifunctional catalyst is an effective strategy for large-scale hydrogen production. In this study, a two-stage electrodeposition method was used to prepare a crystalline-amorphous structure cobalt molybdenum phosphide layered particles with different sizes on a nickel foam (NF) substrate. Electron rearrangement at the Co/CoMoP2@CoMoO4 heterogeneous interface can reduce the reaction energy barrier for HER and OER, and accelerate the catalytic reaction kinetics. The doping of Mo can promote the synergistic effect between Co and Mo, thereby optimizing the Gibbs free energy of hydrogen adsorption/desorption. This layered arrangement of different size particles greatly improves the active area of the catalyst. In alkaline solution, achieving a current density of 10 mA cm−2 only required overpotentials of 40 mV for HER and 278 mV for OER, respectively. The cell voltage required for the CoMo-P/NF||CoMo-P/NF electrolytic cell is only 1.53 V at 10 mA cm−2. This study provides a reference for the rapid, efficient, and environmentally friendly preparation of high-activity water splitting catalysts with large surface areas.