Developing robust and highly bifunctional electrocatalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is key for achieving effective rechargeable Zn-air battery. Herein, a zeolitic imidazole framework is synthesized via pulsed laser ablation in liquid, pyrolyzed into N-doped carbon (NC), and utilized as a self-template for decorating NiCoFePdIr (HEA) nanoparticles (NC-HEA) using a wet chemical approach. The optimized NC-HEA catalyst demonstrates an impressive ORR halfwave potential of 0.86 V vs. a reversible hydrogen electrode (RHE), outperforming Pt/C, and an OER overpotential of 400 mV at 10 mA cm-2, comparable to IrO2. This outstanding activity can be ascribed to the presence of N-rich carbon, enhanced surface area, excellent electronic conductivity, and porous structure, which collectively facilitate effective mass transfer during the ORR and OER. Density functional theory computations demonstrate that the strong interaction within the NC matrix and HEA in the NC-HEA catalyst improves the catalytic activity for both reactions. Furthermore, a rechargeable Zn-air battery incorporating the NC-HEA demonstrates excellent activity, achieving an energy density of 140 mW cm-2 and amazing cycle stability. The proposed method offers a simple and rapid approach for creating progressive oxygen bifunctional electrocatalysts with potential applications across various energy technologies.

Herein, multi-walled carbon nanotubes (CNT) embedded with RuPdIrPtAu-high entropy alloys (HEA) via pulsed laser irradiation in liquids are successfully fabricated. The resultant composite synergistically enhances hydrazine oxidation reaction (HzOR)-boosted water electrolysis. Notably, HEA with approximate to 2-5 nm size, are uniformly distributed across the surface of the CNTs. An optimized HEA/CNT-10 demonstrates exceptional performance in oxygen and hydrogen evolution reactions (OER and HER), depicted by ultralow overpotentials of 30.7 and 330 mV at 10 mA cm-2, respectively. By replacing OER with HzOR, HEA/CNT-10 needs a lower potential of 0.1 V to accomplish 10 mA cm-2, as compared to OER (1.56 V vs. RHE). Moreover, the hydrazine splitting electrolyzer desirable a small voltage of 0.242 V to attain 10 mA cm-2, while maintaining exceptional stability. Experimental and DFT studies validate the cocktail effects and role of multiple metal-sites in HEA/CNT-10, which significantly enhance the efficiency of parallel HER||HzOR processes, highlighting its potential in energy-efficient, hydrogen production. In situ Raman probe indicated the configuration of an acidic environment, monitoring of H3O+, during HER, despite the basic conditions. This is attributed to the dominance of the Heyrovsky step, facilitated by the high catalytic activity of the HEA, coupled with protonation of the CNT surface.

Hydrazine-assisted water splitting presents a capable low-voltage, energy-effective approach to green hydrogen production while addressing hydrazine pollution concerns. Herein, an iridium-decorated CoP nanostructure (Ir/ CoP) is designed and synthesized as an advanced bifunctional electrocatalyst for both the anodic hydrazine oxidation reaction (HzOR) and the cathodic hydrogen evolution reaction (HER). The Ir/CoP-3 catalyst exhibits superior hydrazine electrooxidation with minimal overpotential and enhanced mass activity, alongside improved HER performance. Electrochemical characterization demonstrates that the Ir/CoP-3 catalyst achieves an exceptionally low HER overpotential of 102 mV and an ultralow HzOR operating potential of-14 mV at 10 mA cm-2. Additionally, density functional theory calculations provide deep insights into the bifunctional catalytic activity of the Ir/CoP catalyst. Consequently, the overall hydrazine splitting (OHzS) electrolyzer, configured with Ir/CoP-3(-)||Ir/CoP-3(+), operates at a minimal cell voltage of only 0.125 V at 10 mA cm-2. Remarkably, incorporating the Ir/CoP-3 catalyst as the cathode with a Zn foil anode in a Zn-hydrazine (Zn-Hz) battery delivers a high energy efficiency of 92 % and outstanding cyclic stability. Moreover, self-sustained hydrogen generation is achieved by coupling the Zn-Hz battery with the OHzS electrolyzer, underscoring its strong potential for practical applications.

Highly activated porous carbon materials with a unique architecture, heteroatom incorporation, substantial specific surface area, and promising electrochemical properties are regarded as superior electrode materials for supercapacitor applications. In this study, we synthesized activated porous nitrogen-doped carbon (APNC) using a nitrogen-containing isonicotinic acid organic ligand within a Zn-based metal-organic framework (Zn-MOF) as both a source and template through a facile pyrolysis process with KOH activation. The resulting APNC material with the optimized synthesis conditions exhibited uniform polyhedral morphology, a large specific surface area (1947.9 m2 g-1), and nitrogen heteroatom doping in the carbon framework. These features collectively enhanced its electrochemical performance and ensured exceptional electrochemical stability in a 6 M KOH electrolyte. Electrochemical measurements in a three-electrode setup revealed that the synthesized APNC electrode material accomplished a specific capacitance of 360 F g-1 at 1 A g-1. In addition, APNC provided excellent cycling stability, retaining 95.5% of its capacitance after 50 000 cycles at a high current density of 20 A g-1. Moreover, a coin-cell-type symmetric supercapacitor fabricated from APNC delivered a brilliant energy density of 18.2 Wh kg-1 at a power density of 400 W kg-1. Density functional theory (DFT) calculations further revealed that nitrogen doping, in conjunction with high porosity, markedly improves the electronic characteristics of N-doped porous carbon, thereby enhancing its energy storage capability in supercapacitors. This study highlights the ability of APNC to serve as an inexpensive and highly effective electrode material, establishing its potential for practical applications in high-performance supercapacitors.

The current study presents a quick and simple method for synthesizing Ir nanoclusters decorated on an N-doped carbon (NC) matrix via pulsed laser ablation in liquid, followed by pyrolysis. The resulting Ir-NC material acts as a dual-functional electrocatalyst, efficiently facilitating hydrogen generation through the hydrazine oxidation reaction (HzOR) and the hydrogen evolution reaction (HER) in alkaline seawater. The optimized Ir-NC-2 catalyst exhibits a low operating potential of 23 mV versus the reversible hydrogen electrode for HzOR and a remarkably low overpotential of 24 mV for HER, achieving a current density of 10 mA cm-2 in alkaline seawater, surpassing the performance of the Pt/C catalyst. Notably, the Ir-NC-2 catalyst also demonstrates superior dual-functionality in overall hydrazine-assisted seawater splitting, requiring only 0.1 V at 10 mA cm-2 while maintaining stability. Moreover, density functional theory calculations reveal that the strong electronic interaction between the Ir nanoclusters and the NC matrix enhances mass transfer and electron conductivity, significantly boosting HER activity and accelerating the kinetics of hydrazine dehydrogenation. Consequently, the Ir-NC-2 catalyst performs efficiently in a Zn-hydrazine battery, achieving high energy efficiency of 95.5% and demonstrating excellent stability for 120 h (360 cycles), indicating its potential for practical applications.

Efficient and durable electrocatalysts for the hydrogen evolution reaction (HER) in alkaline seawater environments are essential for sustainable hydrogen production. Zeolitic imidazolate framework-8 (ZIF-8) is synthesized through pulsed laser ablation in liquid, followed by pyrolysis, producing N-doped porous carbon (NC). NC matrix serves as a self-template, enabling Pt nanocluster decoration (NC-Pt) via pulsed laser irradiation in liquid. NC-Pt exhibits a large surface area, porous structure, high conductivity, N-rich carbon, abundant active sites, low Pt content, and a strong NC-Pt interaction. These properties enhance efficient mass transport during the HER. Remarkably, the optimized NC-Pt-4 catalyst achieves low HER overpotentials of 52, 57, and 53 mV to attain 10 mA cm(-2) in alkaline, alkaline seawater, and simulated seawater, surpassing commercial Pt/C catalysts. In a two-electrode system with NC-Pt-4(-)IIIrO2(+) as cathode and anode, it demonstrates excellent direct seawater electrolysis performance, with a low cell voltage of 1.63 mV to attain 10 mA cm(-2) and remarkable stability. This study presents a rapid and efficient method for fabricating cost-effective and highly effective electrocatalysts for hydrogen production in alkaline and alkaline seawater environments.

Herein, we propose a simple and rapid approach for synthesizing a CuS/Ru composite that serves as a bifunctional electrocatalyst to promote hydrogen production and concurrently convert sulfion into a value-added sulfur product. This composite comprises Ru nanoclusters supported on the CuS nanostructure, achieved through simple pulsed laser irradiation in liquid approach. The optimized CuS/Ru-30 electrocatalyst demonstrates remarkable bifunctional electrocatalytic activity, exhibiting a negligible working potential of 0.28 V (vs. RHE) for the anodic sulfion oxidation reaction (SOR) and a minimal overpotential of 182 mV for cathodic hydrogen evolution reaction (HER) to achieve 10 mA cm(-2) of current density. Moreover, the CuS/Ru-30 electrocatalyst shows exceptional selectivity for converting sulfion into valuable sulfur during anodic oxidation reactions. Remarkably, in a two-electrode electrolyzer system utilizing CuS/Ru-30 as both the anode and cathode, the SOR + HER coupled water electrolysis system demands only 0.52 V to reach 10 mA cm(-2), which is considerably lesser compared to the OER + HER coupled water electrolysis (1.85 V). The experimental results and density function theory (DFT) calculations reveal that the strong electron interaction between CuS and Ru nanoclusters generates a built-in electric field, greatly enhancing electron transfer efficiency. This significantly boosts the HER performance and facilitates the adsorption and production of sulfur intermediates. This study presents a rapid and simple strategy for synthesizing a dual-functional catalyst suitable for low-voltage hydrogen generation while facilitating the recovery of valuable sulfur sources.

Designing and synthesizing highly competent and stable electrocatalysts for the hydrogen evolution reaction (HER) in both alkaline and natural seawater media remain major obstacles. Herein, we present an ultrafast synthetic approach for producing AuRuIrPdPt high-entropy alloys (HEAs) through continuous-wave CO2-laser irradiation for 90 s. HEAs synthesized using different CO2-laser powers (30%, 60%, and 90% of the total 25 W laser power) demonstrated distinctive regularly ordered structures with numerous active sites for the HER. The optimized HEA-60 revealed outstanding HER activity with low overpotentials of 37, 34, and 45 mV at 10 mA cm(-2) in alkaline, simulated seawater, and natural seawater, respectively, outperforming a commercial Pt/C catalyst. In situ/operando electrochemical Raman analysis revealed the involvement of metals (M = Pt, Pd, and Ru) in the HER process, with M-H and M-O observed as intermediates rather than M-OH. Moreover, an overall water-splitting assembly using the IrO2(+)& Vert;HEAs-60(-) configuration achieved an exceptionally low cell voltage of 1.62 V to reach 10 mA cm(-2) in a natural seawater electrolyte, demonstrating excellent stability. This study emphasizes the use of an ultrafast CO2-laser-irradiation method for synthesizing extremely stable and active HEAs for hydrogen production via seawater electrolysis.

Electrocatalytic urea oxidation reaction (UOR) has emerged as a promising alternative to the anodic oxygen evolution reaction (OER) in water electrolysis. However, UOR faces challenges like slow kinetics, high energy barriers, and a complex mechanism, necessitating the development of efficient electrocatalysts. Herein, a rapid method is proposed for synthesizing Mo‐doped Ni/NiO (Ni/MNO) nanocomposite as a highly effective UOR electrocatalyst. Mo doping oxidizes Ni2+ to Ni3+, creating abundant active sites for UOR. The Ni/MNO catalyst exhibits remarkable activity for both OER and UOR due to Mo doping, structural modulation, increased active sites, and the presence of Ni3+ ions. Optimized Ni/MNO‐10 shows a low OER overpotential of 280 mV and a UOR working potential of 1.37 V versus reversible hydrogen electrode at 10 mA cm−2, with exceptional stability over 12 h of continuous electrolysis. Notably, urea‐assisted water splitting requires only 1.45 V for 10 mA cm−2, significantly less than the overall water splitting voltage (1.65 V), indicating energy‐efficient hydrogen production. Moreover, the Ni/MNO catalyst exhibits outstanding long‐term stability. This work presents a rapid and effective approach to synthesizing cost‐effective and efficient electrocatalysts for clean energy production and wastewater treatment.

Interfacial coupling of Z-scheme CsSnBr 3 /SnS 2 heterostructure induces a narrowing band gap and reduces carrier recombination rate. Coupling interface and Br vacancy defects of CsSnBr 3 has excellent photovoltaic performance.

The design of high-performance non-noble-metal-based electrocatalysts for electro-oxidation reactions involving splitting of water molecule for energy and environmental applications is the need of the hour. In this study, we report the electrocatalytic performance of a nanocomposite catalyst of FeNi2S4 nanoparticles/CoFe nanowires supported on nickel foam that was prepared by a simple hydrothermal method. The electrocatalyst has several advantages, such as the nanocomposite structure, relatively high electrical conductivity, and synergistic effect between FeNi2S4 and CoFe. These characteristics enhanced the catalytic efficiency of FeNi2S4/CoFe electrode, gaining small overpotentials of 380 and 207 mV for oxygen and hydrogen evolution reactions, respectively, at a current density of 100 mA cm-2. The charge transfer processes are significantly improved by the electron pairs from FeNi2S4 and CoFe, as well as by the enhanced active sites at the electrode -electrolyte interface and their bonding interactions. The electrooxidation of urea was also explored, which showed a lower overpotential of 230 mV to reach 100 mA cm(-2) current density. Interestingly, FeNi2S4/CoFe was successfully employed as cathode and anode for urea-assisted water electrolysis, utilizing 1.56 V to produce 10 mA cm(-2) current density, which is approximately 160 mV below that for water electrolysis, thus verifying the lower energy consumption during electrolysis. These results indicate that nanoparticle and nanowire composite catalysts can be used for wastewater treatment and green energy production applications.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The design and implementation of affordable high-performance electrocatalysts for the oxygen evolution reac-tion (OER) and urea electrooxidation reaction (UOR) are critical for clean and environmentally friendly energy conversion. Herein, we constructed a novel heterostructure interface engineering of double perovskite La2Ni0.5Co0.5MnO6 (LNCM) nanoparticles and MoO3 nanobelt array-supported amorphous polyaniline (PANI; MoO3/P) for high-performance OER and UOR. Structural and morphological analyses confirmed the formation of a heterostructure interface. The optimized La2Ni0.5Co0.5MnO6@MoO3/P (LMP-30) demonstrated electrocatalytic performance with low overpotentials of 300 mV at 10 mA cm-2 (vs RHE) for OER and 0.48 V at 50 mA cm-2 (vs Hg/HgO) for UOR, as well as better stability after testing for 12 h. The improved electrocatalytic performance was attributed to its distinctive hierarchical nanostructure, which had a synergistic effect on modulating the electrical characteristics and an electrochemically active surface area. More importantly, the LNCM nano -particles on the surface of MoO3/P nanobelts can potentially provide more electrocatalytic active sites, excellent charge transport capacity, enhanced electrical properties, and strong electronic contacts between MoO3/P and LNCM.

In this study, we successfully designed a novel Ti3C2 MXene quantum dots (MQDs)-modified In2S3/MQDs/SmFeO3 (IMS) Z-scheme heterojunction. We then investigated the crystal phases, chemical states, morphologies, and band structures of the Z-scheme catalysts in detail. The as-prepared IMS heterojunctions greatly facilitated the photocatalytic degradation of sulfamethoxazole (SMX) and 4-chlorophenol (4-CP) compared with the single and binary catalysts. The degradation of SMX under visible-light using the optimized IMS-3 ternary composite was clearly enhanced, and the degradation rates of 4-CP were 98.0 % and 95.4 % after 120 and 90 min of irradiation, respectively. The significantly enhanced photoactivity of the IMS composite was attributed to the effective spatial separation and charge transfer owing to the introduction of MQDs as charge-transport bridges in the Z-scheme system. Additionally, the unique properties of MQDs further accelerated the surface redox kinetics of the IMS catalyst, thus stimulating the formation of reactive species for pollutant degradation. Furthermore, these results indicate that MQDs not only act as electron mediators but also maintain the strong redox stability of IMS heterojunctions. This study offers a new avenue for developing efficient MQD-based Z-scheme photocatalysts and provides in-depth insights into the SMX degradation mechanism.

The conversion of CO2 into energy fuel is an effective strategy to address energy shortages and environmental problems. To enhance the photocatalytic activity of CO2 reduction, the lead-free halide double perovskite (CH3NH3)(2) AgBiI6 (010) surface is combined with a SnS monolayer to construct a stable SnS/(CH3NH3)(2) AgBiI6 photocatalyst. The bandgap of SnS/(CH3NH3)(2) AgBiI6 is narrow (1.566 eV) compared with the (CH3NH3)(2) AgBiI6 (010) surface, which enhances the absorption of visible light and leads to the redshift of the absorption edge. The interface interaction between the (CH3NH3)(2) AgBiI6 (010) surface and the SnS monolayer causes electron flow from the SnS monolayer to the (CH3NH3)(2) AgBiI6 (010) surface. SnS/(CH3NH3)(2) AgBiI6 has a good Z-scheme band alignment, which facilitates the separation of electron-hole pairs. The electrons accumulate at the CB of the SnS monolayer and participate in the CO2 reduction reaction. In comparison with the (CH3NH3)(2) AgBiI6 (010) surface, SnS/ (CH3NH3)(2) AgBiI6 changes the rate-determination step and reduces the Gibbs free energy from 2.17 to 1.72 eV. The results indicate that SnS/(CH3NH3)(2) AgBiI6 improves the photocatalytic activity of CO2 reduction.

Density Functional Theory (DFT) calculation was used to conduct a systematic theoretical study on the structural, electrical, and optical properties of pure, Ag-doped, Cu-doped, and (Ag, Cu) co-doped BiVO4. The simulated electronic structure showed that the synergistic effect of Ag/Cu co-doping can induce new energy states due to hybridization in the forbidden gap that resulted in decrease in the band gap of BiVO4, which indicates a decline in photogenerated electron-hole pair recombination and an understandable shift of absorption edge towards higher wavelength region. The (Ag, Cu) co-doped BiVO4 has a higher optical absorption intensity than pure Ag or Cu doped BiVO4, demonstrating the synergistic effect of Ag 4d and Cu 3d states. Furthermore, DFT calculations have been analyzed to explore the collective effect of Ag or/and Cu doping and the intrinsic oxygen vacancy defects in BiVO4.

A simple hydrothermal synthesis approach for rGO decorated copper nickel tin sulfide (CNTS-rGO) micro flowers is devised in this research. Due to the depletion of fossil re-sources in the environment, the demand for energy has recently increased tremendously. Here we report the preparation of CNTS with various concentration of GO (Graphene Oxide) (10-50 mg). The prepared material is characterized for its structural and optical properties using XRD, FESEM, XPS, HRTEM, Raman studies and UV-DRS respectively. Surprisingly, graphene oxide incorporated CNTS material demonstrates an initial overpotential due to the abundance of active sites. Due to their unique properties, they prove to be intriguing and promising alternative catalysts. A minimal start overpotential of -235mV, a low Tafel slope of 57 mV dec(-1) and outstanding long-term stability is found among one of the concentrations of rGO. This is the finest HER performance in acidic medium on electro-chemical studies for CNTS-rGO. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.