Water electrolysis is a promising route for centralized hydrogen production when coupled with renewable power sources such as solar or wind energy. Developing earth-abundant, active and stable electrocatalysts for water splitting is a vital but challenging step. Although various noble metal-free materials such as transition metal phosphides, chalcogenides and oxides/hydroxides have been identified as promising candidates to replace active noble metals catalysts for water splitting reactions, further performance optimization is required for cost-effective water splitting. Here, we report our recent efforts towards high performance water splitting electrocatalysts through multi-scale structure engineering on 2D materials. First, we combine nano-structuring, doping, with inorganic/nanocarbon hybridization to develop Fe-doped CoP nanosheet/carbon nanotube (CNT) hybrids for efficient water splitting. These hybrid catalysts endow excellent catalytic activities to both HER and OER in alkaline electrolytes and enable a high-performance two-electrode electrolyzer for overall water splitting to achieve a current density of 10 mA cm-2 at a voltage of ~1.50 V. These excellent catalytic activities are attributed to the effective exposure of the catalytically active surface by suitable nanostructuring, enhanced intrinsic catalytic activity by heteroatom doping and improved charge transfer by hybridizing with CNT. Second, we report an interface engineering strategy to enhance the HER activity of metallic 1T-MoS2 in alkaline and neutral electrolytes through improving the Volmer step by decoration of nickel hydr(oxy)oxides nanoparticles on the surface of 2D MoS2. The hybrid catalysts can drive a cathodic current density of 10 mA cm-2 at an overpotential of ~73 mV for HER in 1 M KOH, about 185 mV less than the original 1T-MoS2. The improved HER activity is attributed to a bi-functional mechanism adopted in these hybrid catalysts where nickel hydr(oxy)oxide promotes the water adsorption and dissociation while the MoS2 facilitates the electron transfer, adsorption and combination of hydrogen.

Multiscale structure engineering on nanosheet hybrids for water splitting electrocatalysis

254th National Meeting (2017)

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