Enhanced Photoelectrochemical Water-Splitting through Application of Layer by Layer (LBL) and Hydrothermal (HT) Methods in TiO2 and α-Fe2O3 Hierarchical Structures

Abstract

Improving solar energy conversion efficiency and reducing energy loss have become critical issues in recent decades. Photoelectrochemical (PEC) water splitting provides an ideal method for solar energy harvesting and is a key factor in decreasing the use of fossil fuels. Thus, it is extremely important to identify cost-effective, highly active, and robust semiconducting photoelectrodes that can reduce the overpotential reaction and increase electrocatalytic efficiency. However, for overall water splitting, it is challenging to identify suitable photocatalysts with efficient band structures and suitable charge separation for electron-hole pairs. Water splitting is conventionally performed using independent layer-by-layer (LBL) or hydrothermal (HT) techniques. However, this research aims to produce a photoanode by applying both HT and LBL methods in sequence to reduce energy loss during the electron transfer process between the two photosystems. In this study, a TiO2 layer was deposited onto fluorine tin oxide (FTO) glass using the LBL method (TiO2/FTO). Subsequently, hematite (α-Fe2O3) thin films that were synthesized using the HT method were deposited onto TiO2/FTO glasses (Fe2O3/TiO2/FTO). The as-prepared and newly-designed photoanode Fe2O3/TiO2/FTO demonstrates a significantly high photocatalytic activity of 7.68 mA/cm2.Thus, by combining the HT and LBL methods, excellent hydrogen production performance in regard to photocatalytic water splitting was achieved. Furthermore, this hierarchical structure provides good chemical stability and is an excellent candidate for large-scale applications.

Bandgap Reduction and Enhanced Photoelectrochemical Water Electrolysis of Sulfur-doped CuBi2O4 Photocathode

“…Anion doping can be one of the solutions. [8,9] This study explored how sulfur doping CBO affected bandgap reduction and PEC water electrolysis properties. Doping BiVO 4 , a well-known photocathode, with sulfur atoms was recently reported to decrease bandgap by 0.3 eV, and to increase carrier diffusion length by ~70% [10].…”

Fabrication of Ruthenium-Based Transition Metal Nanoparticles/Reduced Graphene Oxide Hybrid Electrocatalysts for Alkaline Water Splitting

“…현재 우리는 화석연료 기반의 에너지원을 사용하고 있는데, 화석연료는 연소 과정에서 이 산화탄소, 질소산화물 등을 배출하여 지구온난화와 같은 여 러 가지 환경 문제를 야기할 수 있다 [3,4]. 이러한 이유 로 화석연료를 대체할 신재생 에너지들에 대한 연구가 활 발하게 진행되고 있으며 [5][6][7][8], 그중 수소 에너지는 중량당 에너지 밀도가 최대 142 MJ kg −1 에 이르며 이는 화석연 료의 3~4배에 해당한다 [9].…”