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[Display omitted] Engineering platinum-free catalysts for hydrogen evolution reaction (HER) with high activity and stability is essential for electrochemical hydrogen production. In this paper, we report the synthesis of cobalt-doped AlNi 3 /NiO (Co-AlNi 3 /NiO) electrode with three-dimensional nanoporous structure via chemical dealloying method. Density functional theory (DFT) calculations reveal that Co-AlNi 3 /NiO can accelerate water adsorption / dissociation and optimize adsorption–desorption energies of H* intermediates, thus improving the intrinsic HER activity. Both the introduction of Co and Al can efficiently ameliorate the electronic density around Ni sites of NiO and AlNi 3 , which can effectively reduce the energy barrier towards Volmer–Heyrovsky reaction and thus synergistically promote the hydrogen evolution. Benefiting from the large electrochemical active surface area, high electrical conductivity and electronic effect, the nanoporous Co-AlNi 3 /NiO catalyst exhibits remarkable HER activity with an overpotential of 73 mV at a current density of 10 mA cm−2 in alkaline condition, outperforming most of the reported non-precious metal catalysts. The nanoporous Co-AlNi 3 /NiO catalyst can operate continuously over 1000 h at high current densities with a robust stability. This work provides a new vision for the development of low-cost and efficient electrocatalysts for energy conversion applications. [ABSTRACT FROM AUTHOR]

In this work, Ni and NiFe LDH are coupled on a carbon cloth to synthesize flexible electrocatalysts with superhydrophilic interfaces. DFT calculations demonstrate that the formation of a unique heterostructure induce the redistribution of the surrounding electrons and increase the total density of states near the Fermi energy level, which optimized the Gibbs free energy for hydrogen adsorption. Under alkaline conditions, the HER overpotential is only 36 mv at a current density of 10 mA cm−2, which is fully comparable to noble metal catalysts. [Display omitted] The rational design of morphology and heterogeneous interfaces for non-precious metal electrocatalysts is crucial in electrochemical water decomposition. In this paper, a bifunctional electrocatalyst (Ni/NiFe LDH), which coupling nickel with nickel–iron layer double hydroxide (NiFe LDH), is synthesized on carbon cloth. At current density of 10 mA cm−2, the Ni/NiFe LDH exhibits a low hydrogen evolution reaction (HER) overpotential of only 36 mV due to the accelerated electrolyte penetration, which is caused by superhydrophilic interface. Moreover, an alkaline electrolyzer is formed and provide a current density of 10 mA cm−2 with a voltage of only 1.49 V. It is confirmed by the density functional theory (DFT) that electron from the Ni layer is transferred to NiFe LDH layer, redistributing the local electron density around the heterogeneous phase interface. Thus, the Gibbs free energy for hydrogen adsorption is optimized. This work provides a promising strategy for the rational regulation of electrons at heterogeneous interfaces and the synthesis of flexible electrocatalysts. [ABSTRACT FROM AUTHOR]

Pb SA -Cu/PC with a three-dimensional structure was demonstrated as an efficient CO 2 reduction catalyst to formate. Pb inhibited the formation of COOH*, reduced the energy barrier of rate determining step in the formate formation process, and achieved 97% high formate selectivity. [Display omitted] • Pb SA100 -Cu/CP catalyst is developed by an economical and low-energy method. • The FE formate is 97 % with a partial current density of 27.9 mA cm−2 at − 0.9 V. • The catalyst exhibits ultra-long stability for more than 60 h. • The synergistic action of Pb SA and Cu atoms lowers the RDS for CO 2 RR to fromate. • Single-atom Pb induces Cu charge redistribution and inhibits the formation of COOH*. Exploring highly selective and stable electrocatalysts is of great significance for the electrochemical conversion of CO 2 into fuel. Herein, a three-dimensional (3D) nanostructure catalyst was developed by doping Pb single-atom (Pb SA) in-situ on carbon paper (Pb SA100 -Cu/CP) through a low-energy and economical method. The designed catalyst exhibited abundant active sites and was beneficial to CO 2 adsorption, activation, and subsequent conversion to fuel. Interestingly, Pb SA100 -Cu/CP showed a prominent Faraday efficiency (FE) of 97 % at –0.9 V versus reversible hydrogen electrode (vs. RHE) and a high partial current density of 27.9 mA·cm−2 for formate. Also, the catalyst remained significantly stable for 60 h during the durability test. The reaction mechanism was investigated by density functional theory (DFT), demonstrating that the doping Pb SA induced the electrons redistribution, promoted the formate generation, reduced the rate-determining step (RDS) energy barrier, and inhibited the hydrogen evolution reaction. The study aims to provide a new strategy for developing of single-atom catalysts with high selectivity and stability, which will help reduce environmental pressure and alleviate energy problems. [ABSTRACT FROM AUTHOR]

A novel porous Ni matrix with optimal pore structure and adequate mechanical property is successfully prepared by a modified spark plasma sintering progress, while a self-supporting HER electrode of Ni 3 Se 2 @Porous Ni is subsequently obtained via a facile one-step hydrothermal synthesis. Such the Ni 3 Se 2 @Porous Ni electrode has performed a superior conductivity, excellent catalytic activity and robust durability, which can be attributed to the strong covalent bonding between Ni 3 Se 2 and Ni matrix, abundant active sites of the vertically arranged nanosheets, as well as the metallurgically bonded metal skeleton, exhibiting a fascinating potential for the industrial application. [Display omitted] Developing efficient and durable self-supporting catalytic electrodes is an important way for industrial applications of hydrogen evolution reaction. Currently, commercial nickel foam (NF)-based electrode has been widely used due to its good catalytic performance. However, the NF consisting of smooth skeleton surface and large pores not only exhibits poor conductivity but also provides insufficient space for catalyst decoration and sufficient adhesion, resulting in inadequate catalytic performance and poor durability of NF-based electrodes. In this paper, a novel three-dimensional porous Ni substrate with multangular skeleton surface and small pore structure was prepared by a modified spark plasma sintering technique, and subsequently Ni 3 Se 2 @Porous Ni electrode with a large number of Ni 3 Se 2 nanosheets uniformly distributed on the surface was obtained by one-step in-situ selenization. The electrode exhibits outstanding conductivity and catalytic hydrogen evolution reaction, providing a low overpotential of 183 mV at a current density of 100 mA cm−2. Due to the strong interfacial bonding between Ni and Ni 3 Se 2 , the Ni 3 Se 2 @Porous Ni electrode shows strong durability, which can work stably at 85 mA cm−2 for more than 200 h. This work provides an effective strategy for the rational preparation of metal substrates for efficient and durable self-supporting catalytic electrodes. [ABSTRACT FROM AUTHOR]

We have designed a noble metal-free porous organic polymer (TDA-Trz-POP) having N- and S-rich surface and it showed very low overpotential (129.2 mV w.r.t RHE for 10 mA cm−2 current density) and low Tafel slope (82.1 mV/deg) in the electrochemical water splitting. [Display omitted] Water splitting is a long-standing quest to material research for mitigating the global energy crisis. Despite high efficiency shown by several high cost noble metal containing electrocatalysts in the water splitting reaction, scientists are focused on alternate metal-free carbon or polymer based materials with comparable activity to make the process economical. In this article, we have strategically designed a noble metal-free thiadiazole (TDA) and triazine (Trz) linked porous organic polymer (TDA-Trz-POP) having N- and S-rich surface. Powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR), solid state 13C magic angle spinning nuclear magnetic resonance (MAS-NMR) and X-ray photoelectron spectroscopic (XPS) analyses have been performed to predict its probable framework structure. This scrunch paper type TDA-Trz-POP shows an extravagant potential for the hydrogen evolution reaction (HER) with a low overpotential (129.2 mV w.r.t. RHE for 10 mA cm−2 current density) and low Tafel slope (82.1 mV deg−1). Again, this metal-free catalyst shows oxygen evolution reaction (OER) at 410 mV overpotential w.r.t RHE for 10 mA cm−2 current density with a lower Tafel slope of 104.5 mV deg−1. This bifunctional activity was further tested in two electrodes set-up under different pH conditions. The porosity seems to be a blessing in the electrocatalytic performance of this metal-free electrocatalyst material. Further, the mystery behind the activity of both HER and OER has been resolved through the density functional theory (DFT) analysis. This work provides an insight to the material scientists for low cost, metal-free material design for the efficient water splitting reaction. [ABSTRACT FROM AUTHOR]

Facile synthesis of FeNi alloy-supported N -doped Mo 2 C hollow nanospheres for enhanced oxygen evolution reaction. [Display omitted] • Facile synthesis of FeNi alloy-supported N -doped Mo 2 C hollow nanospheres. • FeNi/Mo 2 C/NC supports strongly accelerated electron transfer, thereby improving the OER kinetics. • FeNi/Mo 2 C/NC hybrids will hold promise in development of electrode materials. The rapid depletion of fossil fuels results in significant environmental pollution. Consequently, researching environmentally friendly and cost-effective electrocatalysts with exceptional oxygen evolution reaction (OER) capabilities holds immense importance in enhancing the efficient utilization of resources. In this paper, a straightforward and cost-effective method was employed to produce Fe-Ni alloy-supported N -doped carbon hollow nanospheres (FeNi/Mo 2 C/NC) using self-assembled molybdenum dopamine spheres (Mo-PDA-HS) as a substrate. The inclusion of iron and nickel addressed the issue of aggregation and collapse in Mo-PDA-HS nanostructures at high temperatures, while adjusting the electronic structure of the composites to achieve efficient OER activity. The composite displayed a low overpotential (η10 mA = 304 mV) and a minimal Tafel slope (41.8 mV/dec-1). This study introduces a simple strategy for constructing structurally robust and non-aggregating Mo 2 C nanostructures, along with a direct method for designing cost-effective and high-performance catalysts for OER. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bifunctional catalyst Fe[ Pc (I) 4 ] + Ni[ Pc (I) 4 ]@NC PDI for ORR and OER is synthesized. • The NC PDI with 2D structure and superior stability was used as support. • Iodine groups in TM[ Pc (I) 4 ] creates a built-in electric field to enhance catalysis. • The synergistic effect of Fe[ Pc (I) 4 ]/Ni[ Pc (I) 4 ] enhances the catalytic performance. • The catalyst has superior performance for ORR/OER in rechargeable Zn-air batteries. In this paper, we report on the preparation and catalysis of a bifunctional molecular catalyst (Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI) for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in rechargeable Zn-air batteries. This catalyst is prepared by self-assembling tetraiodo metal phthalocyanines (Fe[ Pc (I) 4 ] and Ni[ Pc (I) 4 ]) on a 2D N -doped carbon material (NC PDI) through π-π interactions. The introduction of iodine groups in the edge of phthalocyanines controls the density of electron cloud and electrostatic potential around Fe-N/Ni-N sites and constructs a built-in electric field that facilitates directional transport of charges, enhancing the catalytic activity of the catalyst. Density functional theory (DFT) calculations support this mechanism by showing a reduced energy barrier for the ORR rate-determining step (RDS). The Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI exhibits excellent performance outperforming 20 wt% Pt/C and single-molecule self-assembled Fe[ Pc (I) 4 ]@NC PDI and Ni[ Pc (I) 4 ]@NC PDI , with a half-wave potential of E 1/2 = 0.940 V in the ORR process under alkaline condition. During the OER process, Fe[ Pc (I) 4 ]+Ni[ Pc (I) 4 ]@NC PDI exhibited a low overpotential of 298 mV at 10 mA cm−2 under the alkaline condition, which is much better than RuO 2 , Fe[ Pc (I) 4 ]@NC PDI and Ni[ Pc (I) 4 ]@NC PDI. The catalyst also demonstrates excellent catalysis and durability in rechargeable Zn-air batteries. This work provides a simple and specific method to develop efficient multifunctional molecular electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] Designing cost-effective and robust bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desired in hydrogen production from overall water splitting, but still suffers great challenges due to the sluggish catalytic OER/HER kinetics. In this paper, a surface/defect engineering strategy is developed to synthesize three-dimensional (3D) carbon foam (CF)-supported unique hierarchical Co 3 O 4 nanowires@NiO nanosheets core–shell nanostructured catalyst (NiO@Co 3 O 4 /CF) with rich oxygen-vacancies as a novel bifunctional catalyst for alkaline water splitting electrolysis. Benefited from the synergy of the 3D hierarchical core–shell structure and rich oxygen vacancies, the as-obtained NiO@Co 3 O 4 /CF shows both excellent OER (η 200 = 325 mV, η 500 = 374 mV) and HER (η 10 = 104 mV) activities with low Tafel slopes (64.26 mV dec−1 for OER and 109.14 mV dec−1 for HER, respectively) and outstanding stability. A simple overall water splitting electrolysis cell assembled by this bifunctional NiO@Co 3 O 4 /CF as both OER and HER catalysts requires only a cell voltage of 1.53 V to obtain the current density of 10 mA cm−2 and displays a long-term stability. This work has successfully developed an approach for rational design and novel synthesis of metal oxide hybrids as bifunctional electrocatalysts with high activity and stability for overall water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • A strongly coupled CoP-C/CN photocatalyst is prepared by using amorphous carbon layer as intermediate medium. • A new charge transfer pathway was constructed through VDW forces and P-C bonds. • CoP-C/CN exhibits much enhanced charge transfer and separation efficiency. • CoP-C/CN shows superior activity and stability for photocatalytic H 2 evolution by visible light. Enhancing the charge transmission rate at the interface of transition metal phosphide cocatalysts is an efficient technique to reinforce the photocatalytic activity action of semiconductors, but achieving a faster interface charge transfer rate remains a challenge. This paper reported the coupling of a two-dimensional carbon layer supported CoP (CoP C) as a non-noble metal heterostructure catalyst and a two-dimensional porous graphite carbon nitride (CN) photocatalyst to enhance the transmission rate of photogenerated carriers at the interface. Detailed characterizations and mechanism research have confirmed that the P C bond and Van der Waals heterojunction at the interface function as a novel charge transmission channel, which facilitates the effective transfer of photogenerated carriers from CN to CoP. Furthermore, the large contact area exhibited by the 2D/2D Van der Waals heterojunction offers an increased number of active sites for hydrogen evolution reactions. Consequently, the composite material (CoP C/CN) formed by the coupling of CoP C and CN has an enhanced H 2 production rate of 1503 μmol∙g−1∙h−1 (AQY: 3.03 % at 400 nm) and favorable H 2 production stability under visible light irradiation. This investigation not only provides a new idea for the regulation of interface charge transfer pathway but also offers new inspiration for the photocatalytic system's design with the synergistic impacts of 2D/2D VDW heterojunction and chemical bonds. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Cu dendrites constructed on the surface of copper foam were induced by the potential oscillation generated. • The formation process and morphology control method of copper dendrites are demonstrated. • The geometrical confinement effect induces uniform lithium deposition. • The electrochemical performance of copper foam was significantly improved only by structural modification. Dendrite-free lithium is the ultimate goal in achieving the commercial application of lithium metal anode. In this paper, Dendritic Copper Foam Current Collector (DCFC) is prepared by an electrometallurgy method to realize the homogeneous deposition of lithium metal. The deposition behavior of Cu and Li on different interfaces was studied. Firstly, the Cu dendrites constructed on the surface of Cu foam are induced and formed by the potential oscillation generated by the hydrogen evolution reaction. Secondly, the heterogeneous nucleation model reveals that the reason for the dendrite-free lithium deposition on the dendritic copper foam is the geometrical confinement effect. Compared with commercial copper foam, DCFC with hierarchical structure significantly reduces the nucleation energy and deposition overpotential of lithium metal. The in situ optical microscope observation and finite element simulation results confirm our ideas. Electrochemically, DCFC works stably after 1200 h at a lower potential of 36 mV in a DCFC@Li symmetric battery, which is much superior to 75 mV for just 340 h in Cu foam. The ideal collector with a dendritic structure has broad prospects for the practical application of lithium metal anode. [ABSTRACT FROM AUTHOR]