Trifunctional Electrocatalysts Research Articles

Constructing Dual-Phase Co9S8-CoMo2S4 Heterostructure as an Efficient Trifunctional Electrocatalyst for Oxygen Reduction, Oxygen Evolution and Hydrogen Evolution Reactions.

Designing robust, efficient and inexpensive trifunctional electrocatalysts for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is significant for rechargeable zinc-air batteries and water-splitting devices. To this end, constructing heterogenous structures based on transition metals stands out as an effective strategy. Herein, a dual-phase Co9S8-CoMo2S4 heterostructure grown on porous N, S-codoped carbon substrate (Co9S8-CoMo2S4/NSC) via a one-pot synthesis is investigated as the trifunctional ORR/OER/HER electrocatalyst. The optimized Co9S8-CoMo2S4/NSC2 exhibits that ORR has a half-wave potential of 0.86 V (vs. RHE) and the overpotentials at 10 mA cm-2 for OER and HER are 280 and 89 mV, respectively, superior to most transition-metal based trifunctional electrocatalysts reported to date. The Co9S8-CoMo2S4/NSC2-based zinc-air battery (ZAB) has a high open-circuit voltage (1.41 V), large capacity (804 mAh g-1) and highly stable cyclability (97 h at 10 mA cm-2). In addition, the prepared Co9S8-CoMo2S4/NSC2-based ZAB in series can self-drive the corresponding water-splitting device. The dual-phase Co9S8-CoMo2S4 heterostructure provides not only multi-type active sites to drive the ORR, OER and HER, but also high-speed charge transfer channels between two phases to improve the synergistic effect and reaction kinetics.

Cobalt Molybdenum Telluride as an Efficient Trifunctional Electrocatalyst for Seawater Splitting

A mixed-metal ternary chalcogenide, cobalt molybdenum telluride (CMT), has been identified as an efficient tri-functional electrocatalyst for seawater splitting, leading to enhanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). The CMT was synthesized by a single step hydrothermal technique. Detailed electrochemical studies of the CMT-modified electrodes showed that CMT has a promising performance for OER in the simulated seawater solutions, exhibiting a small overpotential of 385 mV at 20 mA cm−2, and superior catalyst durability for prolonged period of continuous oxygen evolution. Interestingly, while gas chromatography analysis confirmed the evolution of oxygen in an anodic chamber, it showed that there was no chlorine evolution from these electrodes in alkaline seawater, highlighting the novelty of this catalyst. CMT also displayed remarkable ORR activity in simulated seawater as indicated by its four-electron reduction pathway forming water as the dominant product. One of the primary challenges of seawater splitting is chlorine evolution from the oxidation of dissolved chloride salts. The CMT catalyst successfully and significantly lowers the water oxidation potential, thereby separating the chloride and water oxidation potentials by a larger margin. These results suggest that CMT can function as a highly active tri-functional electrocatalyst with significant stability, making it suitable for clean energy generation and environmental applications using seawater.

In Situ Electrochemical Oxidation Synthesis of SyA-Cu/CuO/NF Heterostructure As Trifunctional Electrocatalyst for UOR, BOR, and HER at Industrial-Scale High Current Density

In Situ Electrochemical Oxidation Synthesis of SyA-Cu/CuO/NF Heterostructure As Trifunctional Electrocatalyst for UOR, BOR, and HER at Industrial-Scale High Current Density

Boosting the Production of Hydrogen from an Overall Urea Splitting Reaction Using a Tri-Functional Scandium-Cobalt Electrocatalyst.

The creation of highly efficient and economical electrocatalysts is essential to the massive electrolysis of water to produce clean energy. The ability to use urea reaction of oxidation (UOR) in place of the oxygen/hydrogen evolution process (OER/HER) during water splitting is a significant step toward the production of high-purity hydrogen with less energy usage. Empirical evidence suggests that the UOR process consists of two stages. First, the metal sites undergo an electrochemical pre-oxidation reaction, and then the urea molecules on the high-valence metal sites are chemically oxidized. Here, the use of scandium-doped CoTe supported on carbon nanotubes called Sc@CoTe/CNT is reported and CoTe/CNT as a composite to efficiently promote hydrogen generation from highly durable and active electrocatalysts for the OER/UOR/HER in urea and alkali solutions. Electrochemical impedance spectroscopy indicates that the UOR facilitates charge transfer across the interface. Furthermore, the Sc@CoTe/CNT nanocatalyst has high performance in KOH and KOH-containing urea solutions as demonstrated by the HER, OER, and UOR (215mV, 1.59, and 1.31V, respectively, at 10mA cm-2 in 1m KOH) and CoTe/CNT shows 195 mV, 1.61 and 1.3V, respectively. Consequently, the total urea splitting system achieves 1.29V, whereas the overall water splitting device obtaines 1.49V of Sc@CoTe/CNT and CoTe/CNT shows 1.54, 1.48 V, respectively. This work presents a viable method of combining HER with UOR for maximally effective hydrogen production.

High-throughput screening of efficient graphdiyne supported transition metal single atom toward water electrolysis and oxygen reduction

Efficient single-atom electrocatalysts show great potential for application in the field of renewable energy. In this work, dispersion-corrected density functional theory (DFT) calculations based on high-throughput screening were used to identify effective graphdiyne (GDY) supported single-atom electrocatalysts (SAECs) for water electrolysis and the oxygen reduction reaction (ORR). The solvation effect on the electrocatalytic performance of the catalysts was carefully discussed. A general design principle was established to evaluate the activities of TM@GDY SAECs for ORR and oxygen evolution reaction (OER). ΔGOH* could serve as the sole descriptor for the onset potential of OER and ORR. Additionally, a universal structural descriptor φ, which is strongly related to ΔGOH*, was identified. This descriptor only includes intrinsic features such as the number of electrons in d orbitals and elemental electronegativity. Consequently, a structure-activity volcano was plotted. Combined with the electronic properties calculations, the mechanism behind the relationship between ΔGOH* and descriptor φ was deeply analyzed. Among the investigated candidates, TM@GDY (TM = Ni, Pt, Pd, Cu, Co, Rh, and Ag) are potential bifunctional electrocatalysts for OER and ORR. Three non-noble metal-based SAECs (Ni@GDY, Co@GDY, and Cu@GDY) and two noble metal-based SAECs (Rh@GDY and Ag@GDY) are potential trifunctional electrocatalysts for OER, ORR, and the hydrogen evolution reaction.

Trifunctional Graphene-Sandwiched Heterojunction-Embedded Layered Lattice Electrocatalyst for High Performance in Zn-Air Battery-Driven Water Splitting.

Zn-air battery (ZAB)-driven water splitting holds great promise as a next-generation energy conversion technology, but its large overpotential, low activity, and poor stability for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) remain obstacles. Here, a trifunctional graphene-sandwiched, heterojunction-embedded layered lattice (G-SHELL) electrocatalyst offering a solution to these challenges are reported. Its hollow core-layered shell morphology promotes ion transport to Co3S4 for OER and graphene-sandwiched MoS2 for ORR/HER, while its heterojunction-induced internal electric fields facilitate electron migration. The structural characteristics of G-SHELL are thoroughly investigated using X-ray absorption spectroscopy. Additionally, atomic-resolution transmission electron microscopy (TEM) images align well with the DFT-relaxed structures and simulated TEM images, further confirming its structure. It exhibits an approximately threefold smaller ORR charge transfer resistance than Pt/C, a lower OER overpotential and Tafel slope than RuO₂, and excellent HER overpotential and Tafel slope, while outlasting noble metals in terms of durability. Ex situ X-ray photoelectron spectroscopy analysis under varying potentials by examining the peak shifts and ratios (Co2+/Co3+ and Mo4+/Mo6+) elucidates electrocatalytic reaction mechanisms. Furthermore, the ZAB with G-SHELL outperforms Pt/C+RuO2 in terms of energy density (797Wh kg-1) and peak power density (275.8mW cm-2), realizing the ZAB-driven water splitting.

Nanocarbons-Based Trifunctional Electrocatalysts for Overall Water Splitting and Metal-Air Batteries: Metal-Free and Hybrid Electrocatalysts.

Trifunctional electrocatalysts, an exciting class of materials that can simultaneously catalyze hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), can significantly enhance the performance and economic viability of electrochemical energy storage and conversion technologies such as water-splitting electrolyzers, metal-air batteries, fuel cells and their integrated devices. Such multifunctional electrocatalysts encompass multiple active sites that can simultaneously catalyze two or more different electrochemical reactions and are feasible routes for addressing global energy and environmental challenges. This review accounts for nanocarbons-based trifunctional electrocatalysts reported for electrolyzers, metal-air batteries and integrated electrolyzer-battery systems, providing a practical perspective. Metal-free and hybrid (hybrids of nanocarbons and transition metals/compounds) trifunctional electrocatalysts are covered. Given the growing importance of green technologies, we discuss biomass-derived carbon-based trifunctional electrocatalysts separately. The collective information provided in the review could help researchers derive more effective and durable trifunctional electrocatalysts suitable for commercial use.

Nanostructured MnMoO4 as a trifunctional electrocatalyst for overall water splitting and CO2 reduction

Electrochemical water splitting and CO2 reduction are important processes to produce hydrogen and low–carbon fuels as renewable energy sources. Here, nanostructured MnMoO4, prepared by the reflux precipitation method, was investigated as a trifunctional electrocatalyst for overall water splitting and CO2 reduction reactions. Using a combination of diffuse reflectance spectroscopy and electrochemical impedance spectroscopy results, a direct band gap of 3.05 eV was obtained experimentally for the prepared MnMoO4. An overpotential of 0.36 V at a current density of 5 mA cm−2 and a Tafel slope of 58 mV dec−1 were obtained for the oxygen evolution reaction. At a current density of 3 mA cm−2, overpotentials of 0.39 V and 0.58 V were achieved in the absence and presence of CO2 bubbling into a 0.1 M KOH solution, respectively, emphasizing the poisoning effect of CO2 reduction intermediates for the hydrogen evolution reaction. Based on the obtained results, MnMoO4 could be a promising electrocatalyst for water splitting and CO2 reduction reactions.

Transition metal embedded MoS2 as efficient trifunctional electrocatalyst: A computational study

In the advancement of electrochemical energy systems, multifunctional catalysts for the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER) are indispensable. Moreover, catalysts produced by incorporating transition metals into two-dimensional materials via substitutional modification have demonstrated remarkable efficacy. The present study examines the prospective uses of transition metal (TM= Nb, Co, In, and Re) dopants comprising 10% Niobium, Rhenium, Cobalt, and Indium in 2D MoS2. The density functional theory has been utilized to study the atomic level interaction. Based on the result, it can be observed that Nb-doped MoS2 has a ΔGH value of 0.06 eV, which signifies its remarkable HER capability when compared to pristine MoS2 and other doped versions. Our analysis for OER and ORR activities reveals that Co doped MoS2 exhibit superior performance compared to both the pristine and other doped versions of TM-MoS2, with an overpotential value ɳOER = 1.00 V and ɳORR = 0.77 V. A modification in electronic properties is examined by analysing the partial density of states during the HER and OER processes. The number of potential candidates suggested by the present findings will aid in the development of TM-doped MoS2-based electrocatalysts.

Co-Co6Mo6C2 heterostructure grown on carbon nanofibers as tri-functional electrocatalyst for overall water splitting and rechargeable Zn-air batteries

The advancement of cost-effective and efficient electrocatalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) is crucial for the progress of clean energy conversion and storage technologies. In this work, cobalt (Co) and cobalt-molybdenum (Mo) bimetallic carbide (Co6Mo6C2) heterostructure grown on carbon nanofibers (denoted as Co-Co6Mo6C2/CNFs) as tri-functional electrocatalyst were prepared by a four-step method. Benefiting from the electronic structure modulation between the heterostructure to improve the catalytic activity, Co-Co6Mo6C2/CNFs exhibits high catalytic activity for HER (91 mV @ 10 mA cm−2), OER (293 mV @ 10 mA cm−2) and ORR (E1/2=0.80 V). Moreover, Co-Co6Mo6C2/CNFs assembled overall water splitting electrolyzer achieves a current density of 10 mA cm−2 with a battery voltage of only 1.70 V and has long-term durability. Zn-air batteries (ZABs) based on Co-Co6Mo6C2/CNFs has a power density of 156.6 mW cm−2 with good stability. This study contributes to the development of inexpensive and efficient transition metal-based multifunctional electrocatalysts.

A self‐powered system to electrochemically generate ammonia driven by palladium single atom electrocatalyst

AbstractThe utilization of single atoms (SAs) as trifunctional electrocatalyst for nitrogen reduction, oxygen reduction, and oxygen evolution reactions (NRR, ORR, and OER) is still a formidable challenge. Herein, we devise one‐pot synthesized palladium SAs stabilized on nitrogen‐doped carbon palladium SA electrocatalyst (Pd‐SA/NC) as efficient trifunctional electrocatalyst for NRR, ORR, and OER. Pd‐SA/NC performs a robust catalytic activity toward NRR with faradaic efficiency of 22.5% at −0.25 V versus reversible hydrogen electrode (RHE), and the relative Pd utilization efficiency is enhanced by 17‐fold than Pd‐NP/NC. In addition, the half‐wave potential reaches 0.876 V versus RHE, amounting to a 58‐time higher mass activity than commercial Pt/C. Moreover, the overpotential at 10 mA cm−2 is as low as 287 mV for Pd‐SA/NC, outperforming the commercial IrO2 by 360 times in turnover frequency at 1.6 V versus RHE. Accordingly, the assembled rechargeable zinc‐air battery (ZAB) achieves a maximum power density of 170 mW cm−2, boosted by 2.3 times than Pt/C–IrO2. Two constructed ZABs efficiently power the NRR‐OER system to electrochemically generate ammonia implying its superior trifunctionality.

Hollow-Structured Co-MoSx/Graphene Trifunctional Electrocatalyst for Self-Powered Hydrogen Production System.

Developing a single electrocatalyst that can facilitate both rechargeable aqueous metal-air batteries and water splitting has become a crucial focus in renewable-energy technologies. This necessitates addressing the three distinct electrocatalytic reactions: the electrochemical oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Despite significant efforts, the creation of a alkaline medium based trifunctional catalyst with high activity at a low cost has proven to be a considerable challenge. Currently, Pt and its alloys have been considered as the most active catalysts for the ORR and HER, whereas noble-metal oxides such as IrO2 and RuO2 are considered as the golden standards of OER catalyst. However, noble-metals based catalyst have been suffered from their high cost, limited reserves in the Earth’s crust, and poor electrocatalytic stability. Moreover, these noble metals face challenges in simultaneously exhibiting trifunctional catalytic activity for ORR, OER, and HER. In recent study, Transiton metal sulfides(TMSs) have great attraction as trifunctional catalyts due to their eqrth abudance, tunnable band structure, and crystal structure. especially, one of widely used TMCs is MoS2 because of their Pt-like high catalytic activity for HER as well as thermodynamic electrochemical stability and rich catalytic sites in the planar nature. However, the most stable 2H (hexagonal) phase MoS2 suffers from poor electrical conductivity, low wettability, and aggregation indced reducing active catalytic sites and resulting high resistance. 2H MoS2 also shows poor activity for OER and ORR, thereby hampering its practical applications as trifunctional catalyst. To overcome this threshold, various strategies have been conducted to improve their electrochemical charateristics, such as defect engineering, heterojunction foramtion, phase transform and integrating porosity control. However, commonly considered method to synthesis requires complex multi-steps with high temperature, vaccum system, explosive gas, and toxic etchant.In this study, we successfully synthesized the homogeneous growth of a Co-based nanometer-scale metal-organic framework (MOF) on graphene oxide at room temperature. Furthermore, a facile one-pot solvothermal method was employed to synthesize Co-MoSx/Graphene, which consists of a hollow, heterogeneous bimetallic sulfide (Co3S4/MoS2 with Co-S-Mo bonding) within a sandwiched graphene/MoS2 layer, demonstrating superior trifunctional activity and stability. Incorporating a conductive graphene layer between MoS2 layers is an effective strategy for not only realizing high electrical conduction to MoS2 layers, but also increasing MoS2 interlayer spacing for high ion accessibility. Besides, a variety of techniques, including Cs-corrected scanning transmission electron microscope (Cs-STEM), X-ray diffraction(XRD), and X-ray absorption spectroscopy (XAS), are used to confirm the atomic configurations of Co-MoSx/Graphene structure and morphologies. Also, Raman, Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were conducted to investigating the binding structure and chemical states. Furthermore, The internal electric field (IEF) within heterojunction, which induced from the differing electron density of the bimetallic species and the sandwiched graphene are contribute not only electron density structure optimization for enhancing reaction kinetics but also accelerating electron-hole exchange. The IEF in the microporous-heterostructure accelerates the diffusion of reaction intermediate with sufficient mass transport and facilitates a Graphene/MoS2-to-Co-MoSx pathway for enhancing redox kinetics of sluggish OER and ORR. Consequently, the OER and ORR-inactive MoS2, HER, and ORR-inactive Co3S4, along with less catalytically effective graphene, demonstrate outstanding performance when combined in the bimetallic sulfide based highly active heterojunctional structure. To investigate the electrochemical catalytic properties of Co-MoSx/Graphene, Rotating disk electrode(RDE) was used with three electrode measurment. The presence of MoS2/Graphene on Co3S4 and Co-MoSx bonding species in Co-MoSx/Graphene enhances the alkaline electrochemical catalytic activity by reducing overpotential and Tafel slopes(220 mV, 110 mV dec-1 in HER and 320 mV, 55.8 mV dec-1 in OER) under 1M KOH solution. Moreover, the ORR performance was evaluated by using Koutecky-Levich (K-L) Plot with different rotating speeds under 0.1M KOH. The electron transfer number (n) is closed theoretical value of 4.0 also shows outstanding performance of the onset potential, half-wave potential and kinetic current density (0.88 V, 0.67 V, and 10.4 mA cm-2), which is comparable that of Pt/C (0.92 V, 0.8 V, and 10.3 mA cm-2). Furthermore, Co-MoSx/G based rechargeable Zinc-Air battery achieve over 85% of theoretical zinc utilization efficiency and 1.4 times higher power density than a Pt/C + RuO2 air cathode based system. We believe that this work could provide a rational strategy for achieve trifunctional electrocatalyst and high performance self-powered hydrogen production system.This research was supported by the National Research Foundation of Korea (2022M3H4A1A04096482, RS-2023-00229679) funded by the Ministry of Science and ICT.

Boosting the electrocatalytic overall water splitting performance by synergistically coupling N-doped delaminated niobium carbide MXene and N-doped graphitic carbon

A robust trifunctional electrocatalyst based on N-doped delaminated niobium carbide (N-Nb4C3Tx) nanosheets encapsulated by N-doped graphitic carbon (NGC) (abbreviated as N-Nb4C3Tx/NGC) is synthesized, which exhibits a low overpotentials of 96 and 291 mV at 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The superior electrocatalytic performance can be attributed to the synergetic effect of the highly conductive N-Nb4C3Tx and doping of the high-content NGC. The introduction of N species plays an important roles of generating graphitic N-doped carbon species and anchoring N in the carbon matrix, which further boost the electrocatalytic activity. The structure properties and nitrogen content of MXene were regulated by the mass ratio of Nb4C3Tx to hexamethylenetetramine (HMTA). These results indicate that the method of synergistically coupling N-Nb4C3Tx and NGC can boost the HER, OER, and overall water splitting performance, providing a new strategy for the development of economical and efficient MXene based electrocatalysts.

Secondary Heteroatoms (S, P) Optimize the Local Coordination Environment of NiFe Sites as a Trifunctional Electrocatalyst for Overall Water Splitting and Zn–Air Batteries

Secondary Heteroatoms (S, P) Optimize the Local Coordination Environment of NiFe Sites as a Trifunctional Electrocatalyst for Overall Water Splitting and Zn–Air Batteries

Atomically dispersed Au single sites and nanoengineered structural defects enable a high electrocatalytic activity and durability for hydrogen evolution reaction and overall urea electrolysis

The development of exceptionally active and stable trifunctional electrocatalysts is essential to facilitate industrial applications of proton exchange membrane electrolyzers. Rare earth catalysts have a wide range of applications in alkaline solution oxidation, but limitations in their stability and activity prevent their further application. In this paper, Au doped CeO2 coated porous Aux/CeO2 (x = 1,2,3) was designed as a three-function electrocatalyst with excellent performance and stability. At 1 M KOH conditions, both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) reactions exhibit excess potentials of 159.6 and 320.8 mV at a current density of 10 mA cm-2. In addition, when incorporated into an Au2/CeO2 (0.05 mmol, HAuCl4·4H2O) microparticles, the catalyst exhibits the potential of 1.42 V(10 mA cm-2) containing 0.33 M urea in 1 M KOH. Remarkably, for hydrogen production driven by urea electrolysis, Au2/CeO2 demonstrated exceptional performance by requiring only a voltage input of 1.63 V. The reducing agent that forms the Au/CeO2 heterojunction modulates the electronic structure of the Au active site and optimizes the adsorption of the intermediate. In addition, the interaction of the Au monolayer with the CeO2 nanosphere effectively prevents excessive oxidation and dissolution of Au, and the porous hollow structure provides additional exposed active sites and facilitates mass transfer.

Trifunctional Intermetallic PtZn‐Based Electrocatalyst for Integrated Hybrid Acid/Alkali Electrochemical Cell toward Glycerol Conversion and H2 Generation

AbstractThe advancement of renewable energy is intricately relied on the development of diverse sustainable electrochemical devices. Persuing exceptionally efficient multifunctional electrocatalysts is imperative, as it promises to significantly streamline the electrode fabrication process, thereby enhancing the overall effectiveness of these devices. Herein, a trifunctional electrocatalysts of N‐doped carbon (NC) supported intermetallic PtZn catalyst (PtZn‐IMC@NC) are reported, which performs highly attractively toward the electrocatalysis of glycerol oxidation reactions (GOR), oxygen reduction reactions (ORR), and hydrogen evolution reactions (HER). Its effectiveness are demonstrated as electrocatalysts for both the anode and cathode in a hybrid acid/alkali direct glycerol fuel cell (AA‐DGFC) and a hybrid acid/alkali glycerol‐hydrogen electrolyzer (AA‐GHEC). The AA‐DGFC can release an impressive peak power density of 286.8 mW cm−2, while the AA‐GHEC achieves a noteworthy current density of 100 mA cm−2 at a significantly low applied voltage of 0.47 V. Such intermetallic PtZn‐based trifunctional electrocatalyst empowers them to establish a self‐powered integrated electrochemical device with the AA‐DGFC driving the AA‐GHEC. This setup exemplifies efficient valorization of glycerol into formate in both cells and hydrogen production in electrolyzer device. This study sparks innovation across diverse applications of multifunctional electrocatalysts and infuses renewed momentum into the realm of advanced energy devices.

Crystal phase engineering of CoBOx/NiCoP heterostructures as trifunctional electrocatalysts for overall water splitting and urea electrolysis

Rational design of non-precious metal-based catalysts for value-added chemicals production is crucial but still challenging. Herein, a trifunctional electrocatalyst with heterostructures is developed via phosphating and NaBH4 pretreatment of the pristine ZIF-L for overall water splitting and urea oxidation. The as-prepared CoBOx/NiCoP catalyst exhibits superior electrocatalytic performance with only overpotentials of 100, 283 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to reach the current density of 10 and 100 mA cm−2, respectively, and the low potential of 1.35 V to achieve a current density of 100 mA cm−2 for urea oxidation reaction (UOR). Theoretical calculations show that the construction of amorphous/crystalline heterostructure can accelerate the charge transfer between the active site and intermediate, thus enhance the intermediates adsorption and reduce the kinetic barrier toward HER/OER process for enhancing electrocatalytic activity. Importantly, the in-situ Raman spectroscopy discloses that the rapid formation of oxidation-state transition metal oxyhydroxide species would provide more active sites for the oxidation reaction. This multiple electrocatalysis demonstrates the great potential of amorphous/crystalline heterogeneous interfaces for high-performing electrocatalytic conversions.

Self-Supported Fe-Doped MoNi4 Alloy Nanosheet Array as a Trifunctional Electrocatalyst for Water and Urea Splitting

Self-Supported Fe-Doped MoNi₄ Alloy Nanosheet Array as a Trifunctional Electrocatalyst for Water and Urea Splitting

Heterostructured NiO/IrO2 synergistic pair as durable trifunctional electrocatalysts towards water splitting and rechargeable zinc-air batteries: An experimental and theoretical study

Constructing an ultra-durable trifunctional electrocatalyst with high efficiency for HER, OER and ORR has become critical for demanding water splitting and zinc air battery applications. Herein, we demonstrated a rational and efficient strategy to develop a porous nano foam like heterostructured NiO/IrO2 nano foam like electrocatalyst via a facile solvothermal and calcination approach. Experiments revealed that NiO/IrO2-NF shows outstanding HER (ƞ10=42 mV), OER (ƞ10=240 mV), and ORR (E1/2=0.80 V) performances with lower overpotentials than many reported trifunctional electrocatalysts. Theoretical investigations on reaction mechanism of NiO/IrO2-NF, S-IrO2 and S-NiO were carried out using density functional theory calculations. The fabricated water electrolyzer required minimum cell voltage of 1.51 V to reach 10 mA cm−2 current density with outstanding durability of 600 h and insignificant potential loss. Rechargeable zinc air battery with NiO/IrO2-NF air cathode displays a power density of 134.8 mW cm−2 with excellent durability of 100/80/40 h at 2/5/10 mA cm−2.

RuSe2 and CoSe2 Nanoparticles Incorporated Nitrogen-Doped Carbon as Efficient Trifunctional Electrocatalyst for Zinc-Air Batteries and Water Splitting.

The development of affordable, highly active, and stable trifunctional electrocatalysts is imperative for sustainable energy applications such as overall water splitting and rechargeable Zn-air battery. Herein, we report a composite electrocatalyst with RuSe2 and CoSe2 hybrid nanoparticles embedded in nitrogen-doped carbon (RuSe2CoSe2/NC) synthesized through a carbonization-adsorption-selenylation strategy. This electrocatalyst is a trifunctional electrocatalyst with excellent hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) activities. An in-depth study of the effect of Se on the electrocatalytic process was conducted. Notably, the incorporation of Se moderately adjusted electronic structure of Ru and Co, enhancing all three types of catalytic performance (HER, η10 = 31 mV; OER, η10 = 248 mV; ORR, E1/2 = 0.834 V) under alkaline condition with accelerated kinetics and improved stability. Density functional theory (DFT) calculation reveals that the (210) crystal facet of RuSe2 is the dominant HER active site as it exhibited the lowest ΔGH* value. The in situ Raman spectra unravel the evolution process of the local electronic environment of Co-Se and Ru-Se bonds, which synergistically promotes the formation of CoOOH as the active intermediate during the OER. The superior catalytic efficiency and remarkable durability of RuSe2CoSe2/NC as an electrode for water splitting and zinc-air battery devices demonstrate its great potential for energy storage and conversion devices.