Facile preparation of tremella-like TiO2/Cd:ZnIn2S4 photoanode with enhanced photo-electro-chemical (PEC) performance for energy and environmental applications

The realization of solar-driven photoelectrochemical (PEC) process lies in the success development of materials with excellent photoelectric properties. Past reports identified TiO 2 , upon modified with both Cd and ZnIn 2 S 4 (ZIS), exhibits promising PEC performance; however, at the cost of tedious preparation. In view of this, our work proposes a facile one-step hydrothermal strategy to deposit both modifiers onto the pre-obtained TiO 2 nanotubes (NTs), realizing rose-like TiO 2 /ZnIn 2 S 4 (TiO 2 /ZIS) or tremella-like TiO 2 /Cd:ZnIn 2 S 4 (TiO 2 /Cd:ZIS) with improved PEC performances. Interestingly, the thickness of ZIS petals, which deposited on top of TiO 2 NTs, is positively-correlated to its Cd-composition, signifying the substitutional doping of Cd into the unit cell of ZIS. This renders robust ionic interactions between the constituents, prompting the enhanced optical properties of TiO 2 in conjecture to its reduced impedance. As a result, the recombination rate of photo-electric-derived carriers was drastically suppressed, with an improved photocurrent density of 606.2 μA cm −2 recorded by TiO 2 /Cd:ZIS photoanode under solar irradiation. Such performance is 80 times and 5.16 times higher than those of bare TiO 2 NTs and TiO 2 /ZIS counterparts. The photoconversion efficiencies in terms of incident photon-to-current conversion efficiency (IPCE) and applied bias photon current efficiency (ABPE) for TiO 2 /Cd:ZIS were significantly improved too, recorded at 1.12% and 0.38%, respectively, under standard evaluation condition. As summary, our work proposes a facile one-step hydrothermal approach that simultaneously-deposit both Cd and ZIS onto TiO 2 photoanode for an enhanced PEC performance. This opens up a wider horizon for PEC technology , further unlocking its potential in both energy and environmental applications.