A new synthesis route of Bi2S3 with solvothermal deposition in photoelectrochemical hydrogen production

Bi2S3 semiconductor is widely preferred in photocatalytic applications due to its absorption in the visible region and near-infrared regions. In this paper, Bi2S3 is synthesized with a novel S2− source including thiosalicylic acid and 2-thiouracil compounds containing by only a one-step solvothermal method at different pHs (1, 2 and 3 called S_pH1, S_pH2 and S_pH3), apply KCl agent to enhanced surface homogeneity to the most catalytic deposition bath (S_K_pH1) and examine surface morphology, crystal structure, solar light absorption and photoelectrochemical hydrogen production performance. FESEM images show that Bi2S3 nanosphere structures are formed and that changing the pH of the deposition bath and the addition of a KCl surface agent changed the homogeneity of the size of the nanosphere structures. The photoelectrochemical performance test indicates that S_K_pH1 photoanode performs the highest catalytic photocurrent density of 2.28 mA cm−2 (vs. 1.23 V RHE) followed by S_pH1 (1.86 mA cm−2), S_pH2 (1.74 mA cm−2) and S_pH3 (1.40 mA cm−2) in LSV measurement. Mott-Schottky results show Bi2S3 electrodes as a n-type semiconductor and Vfb of S_K_pH1 is the most negative, enabling improved photocatalytic performance. EIS measurement shows that decreasing pH of the deposition bath and KCl addition provide reducing Rct (faradaic process) and Rp with applied 1.23 V (vs. NHE) under 100 mW cm−2.