Effects of Matching Facet Pairs of TiO2 on Photoelectrochemical Water Splitting Behaviors. Issue 7 (12th March 2020)

• Record Type: Journal Article
• Authors: Phawa, Chaiyasit; Prayoonpokarach, Sanchai; Sinthiptharakoon, Kitiphat; Chakthranont, Pongkarn; Sangkhun, Weradesh; Faungnawakij, Kajornsak; Butburee, Teera
• Is Part Of: ChemCatChem. Volume 12:Issue 7(2020)
• Page Start: 2116
• Page End: 2124
• Publication Date: 2020-03-12
• Subjects: Water Splitting -- PEC -- TiO2 -- Crystal Facet -- Artificial Photosynthesis; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201901857
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Engineering crystal facets have been proved as one of the most promising strategies for promoting photocatalytic performance of titanium dioxide (TiO2 ). The earlier research in this field focused on trying to obtain as high ratio of the high energy {001} facet as possible, while later found that the co‐existence of facets is more beneficial. However, controlling crystals to expose suitable facet pairs and facet ratios remains challenging. In this work, we not only comprehensively match possible low‐index facets such as {101}‐{001} and {010}‐{001} facet pairs, but also systematically tune their ratios. Moreover, these faceted particles can be directly grown onto the transparent conductive substrate, which can be directly used as a photoanode. So, their intrinsic behaviors can be precisely evaluated without interference from other exogenous factors such as binders, additives, or assembly skills. Various characterization techniques reveal that both the types of facet pairs and the ratios of facets play crucial roles on photocatalytic behaviors, due to the different electron affinity and dissociative adsorption ability of water molecules on a particular facet. Charge transport and surface chemistry have been thoroughly investigated to identify the underlying mechanism. This work sheds light on a material design strategy considering a suitable match of facet pairs for optimizing photocatalytic performance for a wide variety of applications. Abstract : Photoelectrochemical water splitting : In this work, we match the low‐index facets of TiO2 such as {101}‐{001} and {010}‐{001} pairs, comprehensively tune their ratios in the crystals, and carefully investigate the effects of these factors on PEC water splitting performance. It was found that both the types of facet pairs and the facet ratios have significant effects on the photocatalytic activity, due to the switching in electron affinity and dissociative adsorption ability of water molecules on the surface.