Titanium Nitride Protected Cuprous Oxide Photocathode for Stable and Efficient Water Reduction

Photoelectrochemical water splitting for hydrogen production provides a pollution-free and sustainable way to alleviate the over-reliance on fossil fuels. Cu2O is one of the photocathodes most concerned with superior performance, but it suffers from photocorrosion in the electrolyte, which is unfavorable to hydrogen production. Therefore, a reasonable and simple protection strategy to inhibit the photocorrosion of Cu2O is urgently needed in the long term hydrogen production device. In this work, we proposed a Cu2O-based photocathode protection strategy, which uses atomic layer deposition technology to deposit TiN thin film as the protective layer. The optimized photocathode shows remarkably improved stability: the photocurrent density maintains the initial value of -1.4 mA cm(-2) for more than 35 min at 0 V vs RHE; after 1-h testing, it still remains at 71% of the initial value, with 16-fold enhancement in comparison with that of the bare photocathode. This work offers a way to solve the stability issue of unstable photoelectrodes.

Automated summary

The proposed Cu2O-based photocathode protection strategy using atomic layer deposition technology to deposit TiN thin film as the protective layer significantly enhances the stability of the photocathode. The optimized photocathode maintains the initial photocurrent density for more than 35 minutes at 0 V vs RHE and retains 71% of the initial value after 1 hour of testing, showing a 16-fold enhancement compared to the bare photocathode.