One-step preparation of cobalt phosphate at room temperature for effective photocatalytic H2 evolution

Cobalt phosphate materials were prepared in the present work in one step at room temperature using different raw materials and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and N-2 gas adsorption. Cobalt phosphates exhibit 3D flower-like structures, and the assembly of nanosheets (petals of the flowers) of cobalt phosphate prepared with sodium phosphate and cobalt acetate as raw materials (denoted as CoP(A)) is more incompact than that of cobalt phosphate prepared with diammonium hydrogen phosphate and cobalt nitrate as raw materials (denoted as Co-P(B)) due to the former's mildly basic environment. The cobalt phosphates show relatively high photocatalytic activity for H-2 evolution reaction (HER) in the presence of Eosin Y as a sensitizer in an aqueous triethanolamine solution. The activity of Co-P(A) (0.40 mmol h(-1) g(-1)) exceeds that of Co-P(B) (0.19 mmol h(-1)g(-1)), which can be attributed to a more dispersive nanosheet and larger BET-specific surface area of Co-P(A). The mechanisms of photocatalytic HER and the formation of flower-like Co-3(PO4)(2) were discussed. The present system comprising of only abundant elements contributes toward the development of cost-efficient solar HER to achieve sustainable development. [GRAPHICS] .

Automated summary

Cobalt phosphate materials were prepared using different raw materials at room temperature, showing 3D flower-like structures with varying compactness depending on the raw materials used. The cobalt phosphates exhibited high photocatalytic activity for HER, with CoP(A) showing higher activity than CoP(B) due to its more dispersive nanosheet and larger BET-specific surface area. This work contributes towards the development of cost-efficient solar HER using abundant elements for sustainable development.