Electrodeposited Heterogeneous Nickel-Based Catalysts on Silicon for Efficient Sunlight-Assisted Water Splitting

Selecting moderate semiconducting materials for photoelectrochemical (PEC) cells is essential to achieve high solar-energy conversion. Despite the advantageous features of silicon, such as earth abundance and narrow band gap, silicon suffers from severe photocorrosion. Here, heterogeneous nickel-based catalysts produced via electrodeposition are investigated to expedite water oxidation and protect the silicon from corrosion. The morphology of the catalysts and their PEC performances are demonstrated in detail. Synergistic Ni nanoparticles (NPs)/Ni(OH)2/n-Si photoanode shows a high photocurrent density of 29.6 mA cm−2 at 1.23 V versus RHE and operates over 140 h. Owing to the insufficient photovoltage generated by a single photoanode, we introduce a perovskite/Si tandem solar cell as a voltage supplier. The fabricated wired tandem device shows a photocurrent density of 9.8 mA cm−2, corresponding to a solar-to-hydrogen (STH) conversion efficiency of 12% without external bias. Our work may present a promising pathway toward a design of spontaneous energy conversion devices. [Display omitted] The morphology of Ni-based catalysts is tunable via facile electrodeposition methodsHeterogeneous Ni-based catalysts show synergistic photoelectrochemical propertiesPV-PEC tandem cell exhibits high solar-to-hydrogen conversion efficiency of 12% The development of efficient, stable, and cost-effective photoelectrodes is required to accelerate high solar-energy conversion for practical hydrogen production. Lee et al. report the electrodeposition of heterogeneous nickel-based catalysts (Ni NPs/Ni(OH)2) on silicon and investigate their synergistic photoelectrochemical water oxidation behavior.