Fabricated noble-metal free Co2B/g-C3N4 photocatalyst with 2D/2D structure achieved remarkable water splitting performance from visible to near-infrared wavelengths

Developing noble-metal-free photocatalysts to address the challenges of high recombination rate of electrons and holes and poor optical response is high desirable for water splitting. Herein, cobalt boride (Co2B) nanosheets with amorphous phases ordered in short-range but disordered in long-range was fabricated, and coupled with graphic carbon nitride (CN) photocatalysts in the form of B(delta 1)-Co(delta+)-N(delta-) bonding states through an in-situ chemical reduction method. The optimized Co2B/CN nanohybrids exhibited a H2 evolution rate of 56.86 mu mol/h with the highest AQY up to 22.8 %, outperforming than that of Pt decorated CN. Theoretical calculation by DFT verify the characterization results and show that Co active sites on Co2B have better performance of adsorbing H atoms and desorbing hydrogen. The disordered structure of Co2B nanosheets contributed to water splitting performance by providing abundant active sites while metallic nature of Co2B facilitated electrons transfer and inhibited the recombination of electrons and holes. Moreover, theoretical calculation suggested that the high concentration of free carriers endowed Co2B with an resembled SPR effect, thereby increasing the light response of CN and triggering the reaction from visible-light region extended to the near-infrared region up to 800 nm.

Automated summary

In this study, cobalt boride (Co2B) nanosheets with ordered short-range amorphous phases but disordered long-range structure were synthesized and coupled with graphic carbon nitride (CN) photocatalysts through an in-situ chemical reduction method. The optimized Co2B/CN nanohybrids showed a H2 evolution rate of 56.86 mu mol/h with the highest AQY of 22.8%, outperforming Pt decorated CN. The disordered structure of Co2B nanosheets provided abundant active sites, while the metallic nature of Co2B facilitated electron transfer and inhibited electron-hole recombination.