Premium
Role of Dimensionality for Photocatalytic Water Splitting: CdS Nanotube versus Bulk Structure
Author(s) -
Garg Priyanka,
Bhauriyal Preeti,
Mahata Arup,
Rawat Kuber Singh,
Pathak Biswarup
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201801051
Subject(s) - overpotential , water splitting , photocatalysis , photocatalytic water splitting , nanotube , oxygen evolution , materials science , density functional theory , band gap , chemical physics , valence (chemistry) , electron transfer , nanotechnology , catalysis , photochemistry , chemical engineering , carbon nanotube , chemistry , optoelectronics , computational chemistry , biochemistry , organic chemistry , electrode , electrochemistry , engineering
Using state‐of‐the‐art density functional theoretical calculations, we have modelled a facetted CdS nanotube (NT) catalyst for photocatalytic water splitting. The overall photocatalytic activity of the CdS photocatalyst has been predicted based on the electronic structures, band edge alignment, and overpotential calculations. For comparisons, we have also investigated the water splitting process over bulk CdS. The band edge alignment along with the oxygen evolution reaction/hydrogen evolution reaction (OER/HER) mechanism studies help us find out the effective overpotential for the overall water splitting on these surfaces. Our study shows that the CdS NT has a highly stabilized valence band edge compared to that of bulk CdS owing to strong p–d mixing. The highly stabilized valence band edge is important for the hole‐transfer process and reduces the risk of electron‐hole recombination. CdS nanotube requires less overpotential for water oxidation reaction than the bulk CdS. Our findings suggest that the efficiency of the water oxidation/reduction process further improves in CdS as we reduce its dimensionality, that is going from bulk CdS to one‐dimensional nanotube. Furthermore, the stabilized valence band edge of CdS nanotube also improves the photostability of CdS, which is a problem for bulk CdS.