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The development of electrocatalysts with high activity and stability for oxygen evolution reaction (OER) is critically important, the one being regarded as the bottleneck process of overall water splitting. Herein, we fulfill significant OER improvement in both activity and stability by constructing a class of Ni(OH)-CeO supported on carbon paper (Ni Ce@CP) with an intimate hydroxide (Ni(OH))-oxide (CeO) interface. Such interface largely promotes the OER activity with a low overpotential of 220 mV at 10 mA cm and a small Tafel slope of 81.9 mV dec in 1 M KOH. X-ray photoelectron spectroscopy analysis shows that the intimate interface induced by the strong electronic interactions between Ni(OH) and CeO involves the modulation of binding strength between intermediates and catalysts, making a great contribution to the OER enhancement. Importantly, such intimate interface structures can be largely maintained even after a long-time stability test. We have further demonstrated that, when pairing the NiCe@CP after phosphorization (P-NiCe@CP), the NiCe@CP and P-NiCe@CP assembly is highly active and stable for overall water splitting with a low voltage of 1.68 V at 25 mA cm and negligible stability delay over 30 h of continuous operation, which are much better than the commercial Ir/C and Pt/C.

The design of cost-efficient earth-abundant catalysts with superior performance for the electrochemical water splitting is highly desirable. Herein, a general strategy for fabricating superior bifunctional water splitting electrodes is reported, where cost-efficient earth-abundant ultrathin Ni-based nanosheets arrays are directly grown on nickel foam (NF). The newly created Ni-based nanosheets@NF exhibit unique features of ultrathin building block, 3D hierarchical structure, and alloy effect with the optimized Ni Fe layered double hydroxide@NF (Ni Fe LDH@NF) exhibiting low overpotentials of 210 and 133 mV toward both oxygen evolution reaction and hydrogen evolution reaction at 10 mA cm in alkaline condition, respectively. More significantly, when applying as the bifunctional overall water splitting electrocatalyst, the Ni Fe LDH@NF shows an appealing potential of 1.59 V at 10 mA cm and also superior durability at the very high current density of 50 mA cm .

Although direct hydrogen (H ) oxidation to hydrogen peroxide (H O ) is considered as a promising strategy for direct H O synthesis, the desirable conversion efficiency remains formidable challenge. Herein, highly active and selective direct H oxidation to H O is achieved by using hollow Pd-Sn intermetallic nanoparticles (NPs) as the catalysts. By tuning the catalytic solvents and catalyst supports, the efficiency of direct H oxidation to H O can be optimized well with the hollow Pd Sn NPs/P25 exhibiting H O selectivity up to 80.7% and productivity of 60.8 mol kg h . In situ diffuse reflectance infrared Fourier transform spectroscopy of CO adsorption results confirm the different surface atom arrangements between solid and hollow Pd-Sn NPs. X-ray photoelectron spectra results show that the higher efficiency of Pd Sn NPs/P25 is due to its higher content of metallic Pd and higher ratio of Sn , which benefit H O production and selectivity.

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