Developing low-cost and highly-efficient non-precious metal bifunctional electrocatalysts towards the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is an attractively alternative strategy to solve the environmental pollution problems and energy demands. In this study, metal-organic framework (MOF) derived porous cobalt poly-phosphide (CoP) concave polyhedrons are prepared and explored as superior bifunctional electrocatalysts for the HER and OER. The prepared MOF derived CoP concave polyhedrons show excellent electrocatalytic activity and stability towards the HER and OER in both acidic and alkaline media, with the Tafel slopes of 53 mV dec and 76 mV dec and a current density of 10 mA cm at the overpotentials of -78 and 343 mV for the HER and OER, respectively, which are remarkably superior to those of the transition metal phosphides (TMPs) and comparable to those of the commercial precious metal catalysts. In addition, they also offer efficient catalytic activities and durabilities under neutral and basic conditions for the HER. The results of our study may shed light on the direction towards highly efficient bifunctional TMP electrocatalysts with high phosphorous component.

Lead halide perovskites have received much attention in the field of optoelectronic devices. However, the environment-unfriendly nature and intrinsic instability of these perovskites hamper their commercial applications. In this work, one novel one-dimensional lead-free halide perovskite with high stability, CsCu 2 I 3 , was prepared via an antisolvent-assisted crystallization method. The prepared CsCu 2 I 3 bears a high exciton binding energy of ∼105 meV and a high photoluminescence quantum yield of 12.3%. We fabricated a deep ultraviolet photodetector based on a CsCu 2 I 3 film that is nearly blind to 405 nm visible light but is sensitive to 265 and 365 nm illumination. The device exhibits excellent reproducibility and a high I light /I dark ratio of 22 under 265 nm illumination. Furthermore, the responsivity, specific detectivity, and external quantum efficiency are as high as 22.1 mA/W, 1.2 × 10 11 Jones, and 10.3% under a light density of 0.305 mW/cm 2 , respectively. These findings demonstrate that CsCu 2 I 3 perovskites should have great potential for future optoelectronics.

Fabricating heterostructures to promote the charge separation and doping heteroatom to modulate the band gap of the photocatalysts have been regarded as effective strategies to improve the photocatalytic performance. However, it is still an unresolved issue of doping element and fabricating heterostructures with good contact at the same time. In this study, P nanostructures/P doped graphitic carbon nitride composites (P@P-g-C3N4) were successfully composited by a solid reaction route. Various structural characterizations, including X-ray adsorption near edge structure, indicate that P has been doped into g-C3N4 and P nanostructures were directly grown on g-C3N4 to form heterostructures. As expected, the intimate contacted heterostructured composites exhibit much enhanced light absorption and high-efficiency transfer and separation of photogenerated electron–hole pairs, and consequently, the composites also possess the superior photocatalytic performance in the rapidly degrading RhB and an efficient H2 production rate of 941.80 μmolh–1g–1. Systematical studies combining experimental measurements with theoretical calculations were carried out to expound the underlying reasons behind the distinct performance. This study pave a one-step way to synthesize earth abundant element C, N, and P as novel photocatalysts for photochemical applications.

Self-supported cobalt poly-phosphide nanoneedle arrays (CoP3 NAs) were prepared on carbon fiber paper (CFP) as an integrated 3D efficient bifunctional electrocatalyst.

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