High-performance Electrocatalysts Research Articles

Perovskite-type samarium iron oxide adorned on reduced graphene oxide composite: A high-performance electrocatalyst for OER

The oxygen evolution process (OER), an essential and necessary reaction in water splitting to produce clean hydrogen fuel were investigated using a number of electrocatalysts. Non-noble metal catalysts are increasingly being used in place of noble metal catalysts because of their unique qualities, which include affordability, environmental friendliness and electrocatalytic activity. In this work, SmFeO3/rGO composite is prepared for an anion exchange reaction, which is used as catalyst on nickel foam in 1.00 M KOH electrolyte for OER. The fabricated electrocatalysts were confirmed by X-ray powder diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray (EDX) spectroscopy and scanning electron microscopy (SEM). The BET determined surface area of SmFeO3/rGO composite is 51 cm2/g which is better for OER activity. The distinct structure of the nanocomposite displays increased surface area, increasing active sites with plentiful potential for charge transfer and prolonging the material's life. The electrochemical results represented that composite had lower overpotential (180 mV) with Tafel slope (34 mV/dec), displaying higher charge transfer during OER showing efficient electrocatalytic activity and high reliability of 55h. The reasons for lower overpotential and lower Tafel slope values were increased surface area and enhanced number of active spots in composite and also due to presence of non-kinetic effects that alter the Tafel slope values. The electrocatalyst may be able to facilitate the oxidation reaction based on all of these qualities. As a consequence, created composite reacts with outstanding efficacy for the OER process and energy conversion applications.

Efficient Electrochemical Nitrate Removal by Ordered Ultrasmall Intermetallic AuCu3 via Enhancing Nitrate Adsorption.

Developing a high-performance electrocatalyst for synthesizing ammonia from nitrate represents a promising solution for addressing wastewater pollution and achieving sustainable ammonia production. However, it remains a formidable challenge. Herein, an intermetallic AuCu3 electrocatalyst with high-density active sites is designed and prepared for an efficient nitrate electroreduction to generate ammonia. Remarkably, the Faraday efficiency and yield rate of ammonia at -0.9 V are 97.6% and 75.9 mg h-1 cm-2, respectively. More importantly, after 10 cycles of testing, the removal rate of nitrate can still reach 95.2%. Electrochemical in situ Fourier transform infrared analysis indicates that AuCu3 IM can promote the adsorption of nitrate and enhance ammonia production from nitrate. *NH3, *NO, and *NO2 have been proven to be active intermediates. Theoretical and experimental studies show that the Au site can provide a large amount of *H for nitrate reduction, and the Cu site is conducive to the reduction of nitrate to produce nitrogen-containing products. Meanwhile, AuCu3 intermetallic compounds (AuCu3 IM) can inhibit the dimerization of *H. The power density and ammonia yield of the assembled Zn-nitrate battery reached 2.17 mW cm-2 and 71.2 mg h-1 cm-2, respectively.

Vertical Cross-Alignments of 2D Semiconductors with Steered Internal Electric Field for Urea Electrooxidation via Balancing Intermediates Adsorption.

Single-component electrocatalysts generally lead to unbalanced adsorption of OH- and urea during urea oxidation reaction (UOR), thus obtaining low activity and selectivity especially when oxygen evolution reaction (OER) competes at high potentials (>1.5 V). Herein, a cross-alignment strategy of in situ vertically growing Ni(OH)2 nanosheets on 2D semiconductor g-C3N4 is reported to form a hetero-structured electrocatalyst. Various spectroscopy measurements including in situ experiments indicate the existence of enhanced internal electric field at the interfaces of vertical Ni(OH)2 and g-C3N4 nanosheets, favorable for balancing adsorption of reaction intermediates. This heterojunction electrocatalyst shows high-selectivity UOR compared to pure Ni(OH)2, even at high potentials (>1.5 V) and large current density. The computational results show the vertical heterojunction could steer the internal electric field to increase the adsorption of urea, thus efficiently avoiding poisoning of strongly adsorbed OH- on active sites. A membrane electrode assembly (MEA)-based electrolyzer with the heterojunction anode could operate at an industrial-level current density of 200 mA cm-2. This work paves an avenue for designing high-performance electrocatalysts by vertical cross-alignments of active components.

From Atomic-Level Synthesis to Device-Scale Reactors: A Multiscale Approach to Water Electrolysis.

ConspectusThe development of an advanced energy conversion system for water electrolysis with high efficiency and durability is of great significance for a hydrogen-powered society. This progress relies on the fabrication of electrocatalysts with superior electrochemical performance. Despite decades of advancements in exploring high-performance noble and non-noble metal electrocatalysts, several challenges persist at both the micro- and macrolevels in the field of water electrolysis.At the microlevel, which encompasses electrocatalyst synthesis and characterization, design strategies for high-performance electrocatalysts have primarily focused on interface chemical engineering. However, comprehensive understanding and investigation of interface chemical engineering across various length scales, from micrometers to atomic scales, are still lacking. This deficiency hampers the rational design of catalysts with optimal performance. Under harsh reaction conditions, such as high bias potential and highly acidic or alkaline media, the surface of catalyst materials is susceptible to undergoing "reconstruction", deviating from what is observed through ex situ characterization techniques postsynthesis. Conventional ex situ characterization methods do not provide an accurate depiction of the catalyst's structural evolution during the electrocatalytic reaction, hindering the exploration of the catalytic mechanism.At the macrolevel, pertaining to catalysis-performance evaluation systems and devices, traditional laboratory settings employ a conventional three-electrode or two-electrode system to assess the catalytic performance of electrocatalysts. However, this approach does not accurately simulate hydrogen production under realistic industrial conditions, such as elevated temperatures (60-70 °C), high current densities exceeding 0.5 A cm-2, and flowing electrolytes. To address this limitation, it is crucial to develop testing equipment and methodologies that replicate the actual industrial conditions.In this Account, we propose a multiscale research framework for water electrolysis, spanning from microscale synthesis to macroscale scaled reactor design. Our approach focuses on the design and evaluation of high-performance HER/OER (hydrogen evolution reaction/oxygen evolution reaction) electrocatalysts, incorporating the following strategies: Leveraging principles of interface chemical engineering across various length scales (micrometers, nanometers, and atoms) enables the design of catalyst materials that enhance both activity and durability. This approach provides a comprehensive understanding of the intricate interplay between the catalyst structure and activity, implementing in situ/operando characterization techniques to monitor dynamic interfacial reactions and surface reconstruction processes. This facilitates a profound exploration of catalytic reaction mechanisms, offering insights into the catalyst's structural evolution during the electrocatalytic reaction. We construct a laboratory-scale membrane electrode assembly (MEA) electrochemical reactor capable of operating at high current densities (>1 A cm-2) to evaluate the electrocatalytic performance under simulated industrial conditions. This ensures objective and authentic assessments of the catalyst application potential. Throughout the following sections, we illustrate the application of interface chemical engineering on different length scales in designing diverse electrocatalyst materials. We rely on in situ characterization techniques to gain a profound understanding of the mechanisms behind the HER and OER. Additionally, we describe the development of both acidic and alkaline MEA electrochemical reactors to enhance the precision of electrocatalytic performance evaluation. Finally, we provide a concise overview of the challenges and opportunities in this field.

Enzymatic Mesoporous Metal Nanocavities for Concurrent Electrocatalysis of Nitrate to Ammonia Coupled with Polyethylene Terephthalate Upcycling.

Electrochemical upcycling of waste pollutants into high value-added fuels and/or chemicals is recognized as a green and sustainable solution that can address the resource utilization on earth. Despite great efforts, their progress has seriously been hindered by the lack of high-performance electrocatalysts. In this work, bimetallic PdCu mesoporous nanocavities (MCs) are reported as a new bifunctional enzymatic electrocatalyst that realizes concurrent electrocatalytic upcycling of nitrate wastewater and polyethylene terephthalate (PET) plastic waste. Abundant metal mesopores and open nanocavities of PdCu MCs provide the enzymatic confinement of key intermediates for the deeper electroreduction of nitrate and accelerate the transport of reactants/products within/out of electrocatalyst, thus affording high ammonia Faradic efficiency (FENH3) of 96.6% and yield rate of 5.6mgh-1mg-1 at the cathode. Meanwhile, PdCu MC nanozymes trigger the selective electrooxidation of PET-derived ethylene glycol (EG) into glycolic acid (GA) and formic acid with high FEs of >90% by a facile regulation of potentials at the anode. Moreover, concurrent electrosynthesis of value-added NH3 and GA is disclosed in the two-electrode coupling system, further confirming the high efficiency of bifunctional PdCu MC nanozymes in producing value-added fuels and chemicals from waste pollutants in a sustainable manner.

NdMn1.5Ru0.5O5, a high-performance electrocatalyst with low Ru content for acidic oxygen evolution reaction

A mixed oxide with the crystal structure of the DyMn2O5 family, namely NdMn1.5Ru0.5O5, is reported active for the oxygen evolution reaction (OER) in acidic media. NdMn1.5Ru0.5O5 displays high OER activity of 500 A gRu−1 at 1.5 V. Moreover, is more stable than most Ru oxides reported to date, remaining active for more than 500 cycles between 1.1. and 1.7 V at low scan rate of 10 mV s−1. The high activity and stability are attributed to the Ru cations, as NdMn2O5 exhibits very low OER activity. NdMn1.5Ru0.5O5 has particularly short Ru–Ru distances of 2.60 Å, a value close to the Ru–Ru metallic distances around 2.642 Å. The high activity and durability of NdMn1.5Ru0.5O5 for the OER are also demonstrated in a proton exchange membrane water electrolysis cell by producing a low-loaded anode electrode with 0.5 mgRucm−2. The cell achieves 1.97 V at 0.5 A cm−2, consistent with the performances reported for Ru-based catalysts but with lower Ru loading. This performance is maintained during 100 h of operation. Additionally, NdMn1.5Ru0.5O5 displays visible ORR activity in acidic media, recording an onset potential of 0.85 V at 0.1 mA cm−2. It is noteworthy to highlight the extreme rarity of bifunctional ORR/OER catalysts acidic media.

Rapid plasma preparation of CuO nanowires for efficient ammonia synthesis

The conversion of nitrate into high-value ammonia (NH3) by electrochemical means can significantly reduce environmental pollution and alleviate the energy crisis. The development of easily prepared, high-performance electrocatalysts and understanding the origins of their catalytic activity are crucial. In this study, we rapidly prepared an electrocatalyst (P-CuO-10/CF) using plasma technology, subsequently employed under neutral and low nitrate concentration conditions for electrochemical ammonia synthesis. In situ Raman spectroscopy revealed that the as-prepared material underwent an in situ phase transformation to CuO/Cu, its actual active phase, and the transformed CuO exists in an amorphous structure. This heterogeneous structure demonstrated superior nitrate conversion performance, achieving an ammonia yield of 3.57 mg h–1 cm−2 at -0.6 V vs RHE and a Faradaic efficiency of 95.7 %. This strategy expands the application scope of copper-based materials in electrocatalysis and highlights the promising uses of plasma-prepared materials for electrocatalytic nitrate reduction to generate NH3.

Sustainable and cyclic synthesis of 2D Co(OH)2 nanosheets for scalable production of high-performance electrocatalysts

Ultrathin 2D nanomaterials with extremely large surface area and unique electrochemical properties are considered excellent electrocatalyst candidates for clean energy conversion and environmental applications. However, it is still challenging to prepare 2D catalysts through a scalable and sustainable process that may become suitable for industrial demands. Here, we reported a facile cyclic synthesis method of ultrathin 2D nanomaterials based on the ionic layer epitaxy. By repeatedly refreshing a surfactant monolayer on the solution surface, free-standing 2.2 nm thick hexagonal Co(OH)2 nanosheets were obtained from the water surface at ambient conditions in multiple cycles. These nanosheets exhibited a consistently high OER performance with an average overpotential of 427.4 ± 5.3 mV at 10 mA cm−2. Remarkably, hexagonal NSs could be obtained from a wide range of precursor concentrations which could enable over 84 cycles of synthesis on the same stock precursor solution. It will shed light on the design of autonomous and sustainable synthesis of 2D nanomaterials for advanced electrocatalysis development toward a clean future.

Biphase Pd Nanosheets with Atomic-Hybrid RhOx/Pd Amorphous Skins Disentangle the Activity-Stability Trade-Off in Oxygen Reduction Reaction.

The activity-stability trade-off relationship of oxygen reduction reaction (ORR) is a tricky issue that strikes the electrocatalyst population and hinders the widespread application of fuel cells. Here neoteric biphase Pd nanosheets that are structured with ultrathin two-dimensional crystalline Pd inner cores and ≈1 nm thin atomic-hybrid RhOx/Pd amorphous skins, named c/a-Pd@PdRh NSs, for disentangling this trade-off dilemma for alkaline ORR are developed. The superthin amorphous skins significantly amplify the quantity of flexibly low-coordinated atoms for electrocatalysis. An in situ selected oxidation of the top-surface Rh dopants creates atomically hybrid RhOx/Pd disorder surfaces. Detailed energy spectra and theoretical simulation confirm that these RhOx/Pd interfaces can arouse a surface charge redistribution, causing significant electron deficiency and lowered d-band center for surface Pd. Meanwhile, anticorrosive Rh/RhOx species can thermodynamically passivate the neighboring Pd atoms from oxidative dissolution. Thanks to these amplified interfacial effects, the biphase c/a-Pd@PdRh NSs simultaneously exhibit a superhigh ORR activity (5.92 A mg-1, 22.8 times that of Pt/C) and an outstanding long-lasting stability after 100k cycles of accelerated durability test, showcasing unprecedented electrocatalysts for breaking the activity-stability trade-off relationship of ORR. This work paves a bran-new strategy for designing high-performance electrocatalysts through creating modulated amorphous skins on low-dimensional nanomaterials.

Roles of Oxygen-Containing Functional Groups in Carbon for Electrocatalytic Two-Electron Oxygen Reduction Reaction.

Recent years have witnessed great research interests in developing high-performance electrocatalysts for the two-electron (2e-) oxygen reduction reaction (ORR) that enables the sustainable and flexible synthesis of H2O2. Carbon-based electrocatalysts exhibit attractive catalytic performance for the 2e- ORR, where oxygen-containing functional groups (OFGs) play a decisive role. However, current understanding is far from adequate, and the contribution of OFGs to the catalytic performance remains controversial. Therefore, a critical overview on OFGs in carbon-based electrocatalysts toward the 2e- ORR is highly desirable. Herein, we go over the methods for constructing OFGs in carbon including chemical oxidation, electrochemical oxidation, and precursor inheritance. Then we review the roles of OFGs in activating carbon toward the 2e- ORR, focusing on the intrinsic activity of different OFGs and the interplay between OFGs and metal species or defects. At last, we discuss the reasons for inconsistencies among different studies, and personal perspectives on the future development in this field are provided. The results provide insights into the origin of high catalytic activity and selectivity of carbon-based electrocatalysts toward the 2e- ORR and would provide theoretical foundations for the future development in this field.

Three-Dimensional Network of Highly Uniform Cobalt Oxide Microspheres/MXene Composite as a High-Performance Electrocatalyst in Hydrogen Evolution Reaction.

Due to its affordable cost, excellent redox capability, and relatively effective resistance to corrosion in alkaline environments, spinel Co3O4 demonstrates potential as a viable alternative to noble-metal-based electrocatalysts. Nevertheless, these materials continue to exhibit drawbacks, such as limited active surface area and inadequate intrinsic conductivity. Researchers have been trying to increase the electrical conductivity of Co3O4 nanostructures by integrating them with various conductive substrates due to the low conductivity of pristine Co3O4. In this study, uniform cobalt glycerate solid spheres are first synthesized as the precursor and subsequently transformed into cobalt oxide microspheres by a simple annealing procedure. Co3O4 grown on the surface of Ti3C2Tx-MXene nanosheets (Co3O4/MXene) was successfully synthesized through electrostatic attraction. In order to create a positively charged surface, the Co3O4 microspheres were treated with aminopropyltriethoxysilane. The Co3O4/MXene exhibited a low overpotential of 118 mV at 10 mA cm-2 and a Tafel slope of 113 mV dec-1 for the hydrogen evolution reaction, which is much lower than the pristine Co3O4 at 232 and 195.3 mV dec-1.

Mapping hydrogen evolution activity trends of V-based A15 superconducting alloys

Exploring high-efficiency and low-cost electrocatalysts is valuable for water-splitting technologies. Recently, Si-group compounds have attracted increasing attention in electrocatalysis, considering the abundant Si-group elements on Earth. However, Si-group compounds for HER electrocatalysis have not been systematically studied. In this study, we unveil the activity trends of non-noble metal catalyst A15-type V3M (i.e., V3Si, V3Ge, and V3Sn) superconductors and show that V3Si is the most efficient HER catalyst because of the high electronic conductivity and suitable d-band center. Among them, the V3Si only requires 33.4 mV to reach 10 mA cm−2, and only 57.6 mV and 114.6 mV are required to attain a high current density of 100 mA cm−2 and 500 mA cm−2, respectively. These low overpotentials are close to the 34.3 mV at 10 mA cm−2 of state-of-art Pt/C (20 %) but superior to 168.5 mV of Pt/C (20 %) at 100 mA cm−2. Furthermore, the V3Si illustrates exceptional durability with no obvious decay in the 120 h at the different current densities (i.e., 10–250 mA cm−2). The excellent HER activity of V3Si alloy can be ascribed to the synergies of superior electronic conductivity and suitable d-band center. Moreover, DFT calculations reveal that |ΔGH*| is decreased after introducing the V to Si. Beyond offering a stable and high-performance electrocatalyst in an acidic medium, this work inspires the rational design of desirable silicide electrocatalysts.

Polyoxometalate-derived bi-functional crystalline/amorphous interfaces with optimized d-electron configuration for efficient self-powered hydrazine-seawater splitting

Hydrazine-assisted water electrolysis is a promising energy-efficient strategy for hydrogen production. Nonetheless, developing high-performance bi-functional electrocatalysts towards both hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR) remains great challenges, especially for hydrazine-seawater splitting. Herein, we report a polyoxometalate-assisted in-situ synthesis protocol for constructing bi-functional crystalline/amorphous Pt/MoO3-x interfaces toward both efficient HER and HzOR. The polyoxometalate-derived crystalline/amorphous Pt/MoO3-x interfaces deliver working potentials of only –23 and −41 mV at 10 mA cm−2 for HER and HzOR in seawater electrolyte, respectively. Meanwhile, ultrahigh mass activities of 38.39 AmgPt-1 for HER at −100 mV potential and 23.84 AmgPt-1 for HzOR at 50 mV potential are also achieved, over 30.2 and 52.9 times higher than those of commercial Pt/C. As bi-functional electrocatalysts for overall hydrazine-seawater splitting, the electrolyzer requires a cell voltage of only 55/238 mV at 10/100 mA cm−2, 1.584/1.543 V lower than that of the seawater splitting system. Moreover, a proof-of-concept self-powered hydrazine-seawater electrolysis system driven by direct hydrazine fuel cell is further demonstrated, which achieves a hydrogen production rate of 0.29 mL cm−2min−1. DFT calculations verify that, the crystalline/amorphous interfaces endow Pt/MoO3-x an optimized d-electron configuration with favorable H* adsorption and promoted dehydrogenation kinetics of *N2H4 to *N2H3 in the potential-determining step. This work provides a novel strategy and inspiration toward the design of efficient bi-functional electrocatalysts for hydrazine-assisted hydrogen production from seawater.

Spin Effect to Regulate the Electronic Structure of Ir─Fe Aerogels for Efficient Acidic Water Oxidation.

"Spin" has been recently reported as an important degree of electronic freedom to promote catalysis, yet how it influences electronic structure remains unexplored. This work reports the spin-induced orbital hybridization in Ir─Fe bimetallic aerogels, where the electronic structure of Ir sites is effectively regulated by tuning the spin property of Fe atoms. The spin-optimized electronic structure boosts oxygen evolution reaction (OER) electrocatalysis in acidic media, resulting in a largely improved catalytic performance with an overpotential of as low as 236mV at 10mAcm-2. Furthermore, the gelation kinetics for the aerogel synthesis is improved by an order of magnitude based on the introduction of a magnetic field. Density functional theory calculation reveals that the increased magnetic moment of Fe (3d orbital) changes the d-band structure (i.e., the d-band center and bandwidth) of Ir (5d orbital) via orbital hybridization, resulting in optimized binding of reaction intermediates. This strategy builds the bridge between the electron spin theory with the d-band theory and provides a new way for the design of high-performance electrocatalysts by using spin-induced orbital interaction.

Dual-Mode Imaging of Dynamic Interaction between Bubbles and Single Nanoplates during the Electrocatalytic Hydrogen Evolution Process.

Gas bubble formation at electrochemical interfaces can significantly affect the efficiency and durability of electrocatalysts. However, obtaining comprehensive details on bubble evolution dynamics, particularly their dynamic interaction with high-performance structured electrocatalysts, poses a considerable challenge. Herein, dual-mode interference/total internal reflection fluorescence microscopy is introduced, which allows for the simultaneous capture of the evolution pathway of bubbles and the 3D motion of nanoplate electrocatalysts, providing high-resolution and accurate spatiotemporal information. During the hydrogen evolution reaction, the dynamics of hydrogen bubble generation and their interactions with single nanoplate electrocatalysts at the electrochemical interface are observed. The results unveiled that, under constant potential, bubbles initially manifest as fast-moving nanobubbles, transforming into stationary microbubbles subsequently. The morphology of stationary nanoplates regulates the trajectories of these moving nanobubbles while the pinned microbubbles induce the motion of the electrocatalysts. The dual-mode microscopy can be employed to scrutinize numerous multiphase electrochemical interactions with high spatiotemporal resolution, which can facilitate the rational design of high-performance electrocatalysts.

GO modification with PANI-PpPDA as support material for Pd-Ni and its application for ethanol electrooxidation

Among different renewable energy sources, fuel cells emerged to be a promising solution. However, due to limitations such as high cost and low stability of current commercial catalysts, several approaches are considered to modify them. Graphene oxide (GO) modification via a facile in-situ polymerization of aniline (ANI) and p-phenylenediamine (pPDA) in the presence of GO sheets is the main goal of this study. Pd and Ni as active metals are chemically deposited on the support material. The prepared substrates and catalysts are examined by various structural and electrochemical tests. This study shows that GO-PANI-PpPDA support material has favorable characteristics with 32.64 % higher surface area compared to GO. High surface area and porosity lead to more loading and uniform distribution of metallic particles. GO-PANI-PpPDA/Pd-Ni exhibited superior eligible properties including 29.28 % higher electrochemically active surface area compared to GO/Pd-Ni. This nanohybrid has the lowest charge transfer resistance, highest current density, stability and durability and it loses 5.67 % of the initial current after 15 h. This method shows promising results as an advanced strategy to synthesize low-cost and high-performance Pd-based electrocatalysts on the modified GO.

Activating Interfacial Electron Redistribution in Lattice-Matched Biphasic Ni3N-Co3N for Energy-Efficient Electrocatalytic Hydrogen Production via Coupled Hydrazine Degradation.

The development of high-purity and high-energy-density green hydrogen through water electrolysis holds immense promise, but issues such as electrocatalyst costs and power consumption have hampered its practical application. In this study, we present a promising solution to these challenges through the use of a high-performance bifunctional electrocatalyst for energy-efficient hydrogen production via coupled hydrazine degradation. The biphasic metal nitrides with highly lattice-matched structures are deliberately constructed, forming an enhanced local electric field between the electron-rich Ni3N and electron-deficient Co3N. Additionally, Mn is introduced as an electric field engine to further activate electron redistribution. Our Mn@Ni3N-Co3N/NF bifunctional electrocatalyst achieves industrial-grade current densities of 500 mA cm-2 at 0.49 V without degradation, saving at least 53.3 % energy consumption compared to conventional alkaline water electrolysis. This work will stimulate the further development of metal nitride electrocatalysts and also provide new perspectives on low-cost hydrogen production and environmental protection.

Intercalated PtCo Electrocatalyst of Vanadium Metal Oxide Increases Charge Density to Facilitate Hydrogen Evolution.

Efforts to develop high-performance electrocatalysts for the hydrogen evolution reaction (HER) are of utmost importance in ensuring sustainable hydrogen production. The controllable fabrication of inexpensive, durable, and high-efficient HER catalysts still remains a great challenge. Herein, we introduce a universal strategy aiming to achieve rapid synthesis of highly active hydrogen evolution catalysts using a controllable hydrogen insertion method and solvothermal process. Hydrogen vanadium bronze HxV2O5 was obtained through controlling the ethanol reaction rate in the oxidization process of hydrogen peroxide. Subsequently, the intermetallic PtCoVO supported on two-dimensional graphitic carbon nitride (g-C3N4) nanosheets was prepared by a solvothermal method at the oil/water interface. In terms of HER performance, PtCoVO/g-C3N4 demonstrates superior characteristics compared to PtCo/g-C3N4 and PtCoV/g-C3N4. This superiority can be attributed to the notable influence of oxygen vacancies in HxV2O5 on the electrical properties of the catalyst. By adjusting the relative proportions of metal atoms in the PtCoVO/g-C3N4 nanomaterials, the PtCoVO/g-C3N4 nanocomposites show significant HER overpotential of η10 = 92 mV, a Tafel slope of 65.21 mV dec-1, and outstanding stability (a continuous test lasting 48 h). The nanoarchitecture of a g-C3N4-supported PtCoVO nanoalloy catalyst exhibits exceptional resistance to nanoparticle migration and corrosion, owing to the strong interaction between the metal nanoparticles and the g-C3N4 support. Pt, Co, and V simultaneous doping has been shown by Density Functional Theory (DFT) calculations to enhance the density of states (DOS) at the Fermi level. This augmentation leads to a higher charge density and a reduction in the adsorption energy of intermediates.

Enhanced Alkaline Hydrogen Evolution Reaction via Electronic Structure Regulation: Activating PtRh with Rare Earth Tm Alloying.

Developing high-performance electrocatalysts for alkaline hydrogen evolution reaction (HER) is crucial for producing green hydrogen, yet it remains challenging due to the sluggish kinetics in alkaline environments. Pt is located near the peak of HER volcano plot, owing to its exceptional performance in hydrogen adsorption and desorption, and Rh plays an important role in H2O dissociation. Lanthanides (Ln) are commonly used to modulate the electronic structure of materials and further influence the adsorption/desorption of reactants, intermediates, and products, and noble metal-Ln alloys are recognized as effective platforms where Ln elements regulate the catalytic properties of noble metals. Here Pt1.5Rh1.5Tm alloy is synthesized using the sodium vapor reduction method. This alloy demonstrates superior catalytic activity, being 4.4 and 6.6 times more effective than Pt/C and Rh/C, respectively. Density Functional Theory (DFT) calculations reveal that the upshift of d-band center and the charge transfer induced by alloying promote adsorption and dissociation of H2O, making Pt1.5Rh1.5Tm alloy more favorable for the alkaline HER reaction, both kinetically and thermodynamically.

MoS2/graphdiyne nanotube/MXene 3D-interconnected ternary aerogel: A high-performance electrocatalyst for hydrogen evolution reaction

MoS2 is a promising challenger to Pt for the HER, but we must make it more durable before it can take over the hydrogen production scene. This work fabricated and evaluated a hybrid structure of MXene-graphydine nanotube-MoS2 (MGMX) aerogel toward HER. It showed efficient and stable activity H2 evolution with ƞ10 = 109 mV vs RHE and a Tafel slope of 55 mVdec−1. The catalytic performance results from a synergistic interplay between increased exposed active sites and improved charge transfer within the catalyst. The two-dimensional (2D) islands of double-phase MoS2 are directly deposited onto graphdiyne nanotubes (GDNTs) surface, creating a structurally interesting material with interconnected components. The unique combination of sp and sp2 carbon atoms in the graphdiyne (GDY) makes it an ideal support for catalyst material. The combination of high edge density in metallic MoS2, a conducting MXene framework, and the bridging structure of GDNT significantly enhance the overall HER performance of the ternary aerogel structure.