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[Display omitted] Rechargeable metal batteries such as non-aqueous Li metal batteries and aqueous Zn metal batteries have received increasing attention due to the benefits of the high-energy metal anode. However, the dendric growth on the metal anode extremely leads to restricted cycling performance and potential safety issues. Herein, the MXene-modified conductive framework (MCF) is designed and fabricated as a universal current collector of anode for non-aqueous Li metal batteries and aqueous Zn metal batteries to suppress the dendric Li and Zn growth. The MCF exhibits the merits of good lithiophilicity and zincophilicity, enables an easy Li/Zn nucleation process, and possesses high plating/stripping reversibility. After plating Li/Zn, MCF@Li and MCF@Zn realize a dendrite-free surface, facilitating Li/Zn plating/stripping kinetics. The MCF@Li and MCF@Zn symmetric cell shows a low overpotential of 13 mV at 1 mA cm−2 after 900 cycles and 64 mV at 5 mA cm−2 after 750 cycles (1 mAh cm−2), respectively. Furthermore, the non-aqueous MCF@Li||LiFePO 4 full cells and the aqueous MCF@Zn||active carbon capacitors are assembled and present stable cycling ability and improved rate performance with low polarization. This work provides a universal current collector strategy to meet the requirements of non-aqueous and aqueous metal anodes, which may inspire more designs for metal-based energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of efficient catalysts for hydrogen evolution reaction (HER) from water splitting is one of the most promising strategies to achieve the goal of peak carbon dioxide emissions and carbon neutrality. Herein, Ru nanoclusters decorated MoSe 2 nanosheets supported on a Crepis tectorum fluff biomass-derived hollow carbon tube (Ru-MoSe 2 /CMT) are prepared as the HER catalysts in both alkaline and acidic conditions. The Ru modification induces the transformation of MoSe 2 from 2H phase to 1T phase. Benefiting from the strong water dissociation ability of Ru, Ru-MoSe 2 /CMT exhibits a low overpotential of 70 mV with a Tafel slope of 39 mV dec-1 in 1 M KOH. Furthermore, the assembled Ru-MoSe 2 /CMT || RuO 2 system with a low cell voltage of 1.54 V at 10 mA cm−2 exhibits outstanding overall water splitting performance superior to Pt/C || RuO 2 system. The Ru-MoSe 2 /CMT || RuO 2 system also achieves the excellent stability of up to 30 h in 1 M KOH. The synergy effect between Ru and MoSe 2 , as well as the improved electron transfer kinetics provided by the biomass-derived carbon substrate together contribute to the excellent HER activity of Ru-MoSe 2 /CMT. [ABSTRACT FROM AUTHOR]

[Display omitted] • RuNi 1 Co 1 alloy nanoparticles embedded in the hollow carbon tubes with a mosaic structure was prepared. • The DFT calculations indicate that the addition of Ru could optimize the hydrogen adsorption free energy of Ni and Co sites. • RuNi 1 Co 1 @CMT exhibits considerable HER and OER activities, and a low cell voltage was required for the overall water splitting system. • RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system can be driven by a solar panel, which realized green and sustainable hydrogen production. The development of efficient bifunctional catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for reducing the cost of hydrogen production by water splitting. Herein, hollow microtubes composed of RuNi 1 Co 1 alloy nanoparticles uniformly embedded in the carbon matrix (RuNi 1 Co 1 @CMT) are prepared through a simple impregnation followed by reduction. Benefiting from the unique mosaic structure and the synergistic effect between Ru and NiCo, RuNi 1 Co 1 @CMT achieves more exposed active sites and improved reaction kinetics. As a consequence, RuNi 1 Co 1 @CMT exhibits considerable catalytic activities with the overpotentials of 78 mV for HER and 299 mV for OER at 10 mA cm−2 in 1 M KOH. In addition, RuNi 1 Co 1 @CMT exhibits excellent stability for up to 30 h in both HER and OER processes at 20 mA cm−2, which is attributed to the protection of the RuNi 1 Co 1 alloy particles by the carbon layer. Furthermore, the assembled RuNi 1 Co 1 @CMT || RuNi 1 Co 1 @CMT overall water splitting system shows a cell voltage of 1.58 V at 10 mA cm−2. The density functional theory (DFT) calculations indicate that the addition of Ru can optimize the hydrogen adsorption free energy of Ni and Co sites. Finally, a solar panel-driven water splitting device is built, which can realize green and sustainable hydrogen production. The fabrication of RuNi 1 Co 1 @CMT provides a new way for the preparation of effective alloy nanomaterials for energy storage and conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoSe 2 -MoSe 2 (1–1)/rGO has good HER activity in both acidic and alkaline media. • The CoSe 2 -MoSe 2 (1–1) nanosheets uniformly decorate the rGO matrix. • DFT results verify CoSe 2 -MoSe 2 (1–1) heterostructure owns small band gap and ΔG H*. • The rGO matrix and heterojunction structure improve the electronic conductivity. It is important to develop novel energy to solve energy shortage and environmental problems. Hydrogen evolution reaction (HER) is envisaged as a viable technology that can be used to develop sustainable clean energy. Herein, we report a catalyst with CoSe 2 -MoSe 2 heterostructure grown on reduced graphene oxide with an optimum Co/Mo proportion of 1:1 (CoSe 2 -MoSe 2 (1–1)/rGO). It exhibits good HER activities in both acidic and alkaline conditions. The CoSe 2 -MoSe 2 (1–1)/rGO shows an overpotential of 107 mV at 10 mA cm−2 with a Tafel slope of 56 mV dec−1 under acidic condition. Meanwhile, CoSe 2 -MoSe 2 (1–1)/rGO also presents an overpotential of 182 mV at 10 mA cm−2 and with a Tafel slope of 89 mV dec−1 under alkaline condition. These impressive performances of the catalyst are mainly due to the excellent electronic transmission capability of rGO and the abundant active sites of CoSe 2 -MoSe 2 heterostructure as well as the optimized hydrogen adsorption energy of CoSe 2 -MoSe 2 interface. The design of CoSe 2 -MoSe 2 (1–1)/rGO provides a meaningful guide for manufacturing electrode in energy storage and conversion. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeSe 2 -MoSe 2 (1-1)/rGO has good HER activity in both acidic and alkaline media. • FeSe 2 -MoSe 2 (1-1)/rGO has well stability in both acidic and alkaline media. • On the morphology, FeSe 2 -MoSe 2 nanoparticles uniformly decorate the rGO matrix. • DFT results verify the FeSe 2 -MoSe 2 (1-1)/rGO owns small work function. It is of great significance to develop inexpensive and high-efficiency electrocatalysts for the hydrogen evolution reaction (HER). In this work, we synthesized iron molybdenum selenide (FeSe 2 -MoSe 2) loaded on reduced graphene oxide (FeSe 2 -MoSe 2 /rGO) by a one-step hydrothermal method. We further optimized the Fe/Mo ratio and determined the best ratio to be 1-1. In acidic (or alkaline) solution, the optimized FeSe 2 -MoSe 2 (1-1)/rGO has a small Tafel slope of 55 (or 80) mV dec−1 and needs an overpotential of 101 (or 178) mV to achieve 10 mA cm−2. These good properties are mainly due to the structure of bimetallic selenides combining rGO. Moreover, rGO enhances the electrical conductivity. Furthermore, the synergistic effect between FeSe 2 -MoSe 2 (1-1) and rGO results in better HER performance. Density functional theory (DFT) calculation proves that FeSe 2 -MoSe 2 (1-1)/rGO has a small work function. Based on our reasonable design and analysis, FeSe 2 -MoSe 2 (1-1)/rGO is expected to be an efficient and robust catalyst for large-scale applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrocatalytic water splitting used for generating clean and sustainable hydrogen (H 2) can be very promising to address current energy shortage and associated environmental issues. However, this methodology is severely impeded by the tardy oxygen evolution reaction (OER). Hence, designing a preferable kinetics and thermodynamics oxidation reaction that supersede OER is very significant for the energy-saving production of H 2. Herein, hollow needle-like copper cobalt sulfide was constructed on carbon cloth (CuCo 2 S 4 /CC) as a bifunctional electrocatalyst to accelerate H 2 generation and simultaneously convert ethanol into value-added acetic acid. Thanks to the synergistic effect and unique structure of Cu and Co, CuCo 2 S 4 /CC displays superior catalytic activity and durability in ethanol oxidation reaction (EOR) with a low potential of 1.38 V vs. RHE (@10 mA cm−2). Meanwhile, it exhibits excellent hydrogen evolution reaction (HER) performance. The homemade CuCo 2 S 4 /CC//CuCo 2 S 4 /CC ethanol–water electrolyser only demands a voltage of 1.59 V to deliver 10 mA cm−2, 150 mV less than that used for ordinary water splitting. This shows that the ethanol–water electrolyser elaborated here holds encouraging potential in the energy-saving production of H 2 and oxidation of ethanol into value-added acetic acid. This present work may open the way for the rational design of other electrocatalysts for efficient biomass oxidation reaction and relevant H 2 production applications. [ABSTRACT FROM AUTHOR]

The Mo 2 C@C catalyst was prepared by the calcination method under the argon gas flow of the activated walnut shell-ammonium heptamolybdate hybrid powder mixture, enhancing the electrocatalytic hydrogen evolution process. • The waste walnut shell powder was chosen as the carbon source for HER catalysts. • The walnut shell powders derived carbon matrix can enhance the electron transfer. • The open pores can facilitate electrolyte permeation and hydrogen release. Herein, we choose the waste walnut shell as the carbon source, and ammonium heptamolybdate as the molybdenum source to prepare the β-Mo 2 C catalyst supported on carbon matrix (Mo 2 C@C) by the calcination method for hydrogen evolution reaction (HER). The open pores in the porous Mo 2 C nanoparticle clusters can facilitate electrolyte permeation and hydrogen molecules release as well as the carbon matrix can enhance the conductivity. As a result, the optimal Mo 2 C exhibits an efficient HER performance, with an overpotential of 140 mV at 10 mA cm−2 and a Tafel slope of 63 mV dec−1 as well as excellent electrochemical stability. The strategy changing waste walnut shell into the effective catalysts sets an example for the searching and designing rational energy materials. [ABSTRACT FROM AUTHOR]