Photocatalytic Anaerobic Dehydrogenation of Alcohols over Metal Halide Perovskites: A New Acid-Free Scheme for H₂ Production

Abstract

Photocatalytic H2 evolution from haloid acid (HX) solution by metal halide perovskites (MHPs) has been intensively investigated; however, the corrosive acid solution severely restricts its practical operability. Therefore, developing acid-free schemes for H2 evolution using MHPs is highly desired. Here, we investigate the photocatalytic anaerobic dehydrogenation of alcohols over a series of MHPs (APbX3, A = Cs+, CH3NH3 + (MA), CH­(NH2)2 + (FA); X = Cl–, Br–, I–) to simultaneously produce H2 and aldehydes. Via the coassembly of Pt and rGO nanosheets on MAPbBr3 microcrystals, the optimal MAPbBr3/rGO-Pt reaches a H2 evolution rate of 3150 μmol g–1 h–1 under visible light irradiation (780 nm ≥ λ ≥ 400 nm), which is more than 105-fold higher than pure MAPbBr3 (30 μmol g–1 h–1). The present work not only brings new ample opportunities toward photocatalytic H2 evolution but also opens up new avenues for more effective utilization of MHPs in photocatalysis.

Crystal structure engineering of metal halide perovskites for photocatalytic organic synthesis

“…S9, ESI†), confirming the efficient transfer of charge carriers in Cs 3 Bi 2 Br 9 . 24–26 This is further corroborated by the surface charge transfer efficiency ( η t ) measurements 25,27 (Fig. 3B), the η t of Cs 3 Bi 2 Br 9 and Cs 3 Bi 2 Br 9 is calculated to be 24% and 31%, respectively.…”

Crystal phase engineering of Ru for simultaneous selective photocatalytic oxidations and H2 production

“…This can be explained by the reduction of S 2 O 8 2− to SO 4 2− by the photoelectrons, thus competing with the H 2 generation. 45 Notably, both BAD and H 2 production are decreased due to the introduction of AO, demonstrating that the protons for the H 2 production originate from the BA oxidation and that the hole-induced BA oxidation is the rate determining step.…”

“…These results show that the introduction of Ru NPs strongly increases the current densities of the Ru/TiO 2 composites, compared to the bare TiO 2 , at a similar potential range and decreases the overpotential, this accelerates the H 2 production kinetics, facilitating the reduction of protons into H 2 , consequently, resulting in a high H 2 evolution activity. 45,46…”

“…This can be explained by the reduction of S 2 O 8 2− to SO 4 2− by the photoelectrons, thus competing with the H 2 generation. 45 Notably, both BAD and H 2 production are decreased due to the introduction of AO, demonstrating that the protons for the H 2 production originate from the BA oxidation and that the hole-induced BA oxidation is the rate determining step. In situ electron paramagnetic resonance (EPR) was performed to further unravel the reaction mechanism by demonstrating the presence of reaction intermediates during the oxidation of BA into BAD by using 5,5-dimethyl-1-pyrroline-Noxide (DMPO) as a spin-trapping agent.…”

“…These results show that the introduction of Ru NPs strongly increases the current densities of the Ru/TiO 2 composites, compared to the bare TiO 2 , at a similar potential range and decreases the overpotential, this accelerates the H 2 production kinetics, facilitating the reduction of protons into H 2 , consequently, resulting in a high H 2 evolution activity. 45,46 Photoluminescence measurements of TiO 2 and the Ru/TiO 2 composites were performed to probe the radiative recombination of photogenerated charge carriers. 47,48 Similar PL was observed for TiO 2 and the Ru/TiO 2 composites, as shown in Fig.…”