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S-doped CoP nanoneedles assembled urchin-like structure on carbon cloth is prepared to demonstrate the boosting effects of nonmetal element doping and morphology controlling engineerings on OER performances for alkaline water splitting. [Display omitted] • S-doped CoP nanoneedles assembled urchin-like structure is grown on carbon cloth. • S doping brings more active sites and enhanced catalysis kinetics. • Nanoneedles assembled urchin-like structure benefit high surface area fast charge transfer. • Improved OER efficiency in alkaline media are obtained. The electrocatalysts with low-price and high-efficiency for oxygen evolution reaction (OER) are of significant importance for water splitting, which is believed as the promising technique for future sustainable energy system. Herein, sulfur is doped into carbon cloth supported CoP nanoneedles assembled urchin-like structure to acquire improved intrinsic catalysis efficiency, fast charge diffusion, and additional catalysis sites for enhanced OER performance. The specific urchin-like assembly structure is beneficial for highly exposed active sites and short charge transfer path for catalysis. Benefited from the advantages, the obtained sample exhibits advanced OER activity even better than RuO 2 in alkaline solution, achieving low overpotentials of 248 and 380 mV at current densities of 10 and 100 mA cm−2, respectively. This study may set a blueprint for exploring efficient transition metal pounds based catalyst for water splitting with nonmetal doping engineering. [ABSTRACT FROM AUTHOR]

• Electrochemical activation induces surface reconstruction of CoMo-LDH nanosheets. • The optimized electronic structure and enhanced intrinsic activity are obtained. • The increased catalysis sites and promoted charge transfer are achieved. • Generating 100 mA cm−2 at low overpotentials of 202 mV for HER. Surface reconstruction emerging in the electrochemical oxygen evolution process is regarded to be significantly important for the activated catalysis efficiency, however, which is rarely recognized for hydrogen evolution reaction (HER). Here, the electrochemical activation of CoMo layered double hydroxide (CoMo-LDH) nanosheet arrays is demonstrated to significantly activate the electrochemical HER property. The catalysis performance improvement originates from the surface transformation of CoMo-LDH to Co(OH) 2 /CoOOH, as well as the dissolution of Mo and its adsorption on the catalyst surface in K 2 Mo 3 O 10 phase. Based on the combined benefits of optimized electronic structure, increased catalysis sites, and promoted charge transfer, the overpotentials at catalysis current densities of 10 and 100 mA cm−2 are as low as 113 and 202 mV. This study demonstrates the electrochemical activation strategy to drive the surface reconstruction of bimetal hydroxides for enhanced HER performance, inspiring the research interests on the reconstruction and activation enhancement behaviors of HER electrocatalysts. [ABSTRACT FROM AUTHOR]

• Co-doped Ni 3 S 2 nanosheets assembled flower-like structure is grown on NF. • Co doping brings more active sites and enhanced catalysis kinetics. • Ultrathin nanosheets benefit high surface area and fast charge transfer. • Improved OER performances in alkaline media are achieved. Oxygen evolution reaction (OER) sets the huge obstacle for water electrolysis application, and the low-cost catalysts with small overpotential and fast kinetics are highly needed. Herein, cobalt-doped Ni 3 S 2 nanosheets constructed flower-like architecture is grown on nickel foam (Co-Ni 3 S 2 /NF) toward OER application. It is found that, heteroatom doping induces positive effects for OER, including the modulated electronic structure, more active sites, and accelerated charge transfer. Nanosheets structure assures exposed active sites and shortened charge transfer path. Benefited from the aforementioned advantages, the as-prepared sample exhibits impressive catalysis performances, such as ultralow overpotential of 160 mV at current density of 10 mA cm−2, small Tafel slope of 49 mV dec−1, and high stability, which behaves as the promising catalyst for OER. [ABSTRACT FROM AUTHOR]

Transition metal based materials with hollow structure are considered as advanced electrocatalysts for oxygen evolution reaction (OER). This study reports the NiCo-LDH nanosheets assembled hollow structure arrays on nickel foam, which are synthesized by solvothermal method with ZnCo-MOF nanopolyhedra as precursors. Taking advantage of the nanosheets constructed hollow structure, the obtained sample exhibits good OER catalysis activity with low overpotential of 303 mV at current density of 100 mA cm−2 and satisfied stability. It is demonstrated that Ni2+ and Co2+ are oxidized into Ni3+ and Co3+, which play as robust catalysis sites and greatly promote the catalysis performance for OER. This work demonstrates a promising strategy for controllable preparation of hollow structures of transition metal materials for electrochemical water splitting. NiCo-LDH nanosheets assembled hollow architecture arrays on nickel foam are prepared for advanced OER application due to the structural advantages and the robust active sites of oxidized Ni and Co elements. [Display omitted] • NiCo-LDH nanosheets assembled hollow structure arrays are synthesized. • Structural advantages improve surface area and active sites for OER. • Ni and Co are oxidized to high chemical states to promote OER. • Low overpotential of 303 mV at 100 mA cm−2 is obtained for OER. [ABSTRACT FROM AUTHOR]

• PANI coated Ni 3 Mo 2 P-MoO 3 nanoarrays on nickel foam is prepared. • N species in PANI and metals in NiMoOP form metal-N bonds. • The coupling effect improves the intrinsic OER activity. • Enhanced charge transfer resistance and more active sites are obtained. • High OER activities of 290 and 412 mV at 100 and 400 mA cm−2. To obtain high-efficiency and affordable electrocatalysts for water splitting application, constructing specific nanostructures is believed as an effective solution to pursue advanced structure characteristics for improved catalysis property. In this work, a shell-core structured catalyst of polyaniline coated hybrid Ni 3 Mo 2 P-MoO 3 nanoarrays is designed for oxygen evolution. The polyaniline shell not only assures merit of high conductivity for accelerated charge transfer, but also benefits the catalysis stability. The coupling effect between nitrogen species of polyaniline shell and metals of core materials imparts improved intrinsic catalysis activity and more active sites. Hence, the present sample manifests excellent catalytic efficiency for alkali water oxidation, only needing low overpotentials of 290 and 412 mV at high current densities of 100 and 400 mA cm−2, respectively. The development of shell-core catalyst using polyaniline as shell material paves a way for activating other transition metal catalytic materials and supplies a basis for industrial water splitting applications. [ABSTRACT FROM AUTHOR]