Controlling shape anisotropy of hexagonal CdS for highly stable and efficient photocatalytic H₂ evolution and...

Photocorrosion and low solar conversion efficiency hindered widely applications of CdS in photocatalytic (PC) H₂ evolution and photoelectrochemical (PEC) water splitting. Hence, this work reports the shape anisotropy of hexagonal CdS possesses highly stable and efficient PC H₂ evolution and PEC water splitting by simply mixed diethylenetriamine (DETA) and deionized water (DIW) solvothermal. Here we demonstrate that the shape of hexagonal CdS plays an important role in their PC activity. The CdS-Nanorod yields optimal 5.4 mmol/g/h PC H₂ production and photocurrent density 2.63 mA/cm² at open circuit potential (OCP). The enhanced performance is attributed to the effective separation and transport of the photogenerated electron-hole pairs, which were verified by PL and transisent absorbance. Moreover, hexagonal CdS-Nanorod shows long-term PC H₂ production and highly stable photocurrent density. As compared with CdS-Nanosphere, the hexagonal CdS-Nanorod exhibits 27 times and 19.2 times in H₂ production and photocurrent density, respectively. What's more, STH efficiency of hexagonal CdS-Nanorod is 3.23% and an impressive applied bias photon-to-current efficiency (ABPE) is 2.63% at 0.134 V (vs. RHE). Temperature is also explored and reported. The possible mechanism of PC H₂ evolution and PEC water spiltting are proposed for CdS-Nanorod. This work may provide a promising strategy to fabricate efficient PC and PEC systems for solar-to-fuel energy conversion.