화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.45, No.11, 6487-6499, 2020
Design of efficient Mn-doped alpha-Fe2O3/Ti-doped alpha-Fe2O3 homojunction for catalyzing photoelectrochemical water splitting
To produce clean chemical fuel of hydrogen efficiently, applying photocatalysts for conducting photoelectrochemical water splitting is indispensable. Hematite (alpha-Fe2O3) has been considered as one of the most effective photocatalysts for water oxidation due to excellent visible-light responses, high stability and source abundance properties, but low electrical conductivity and slow oxidation evolution kinetics limit its application. In this study, a novel alpha-Fe2O3 homojunction is constructed via doping Ti and Mn in two layers using two-step hydrothermal synthesis followed by one-step annealing process. Co-doping effect of Ti and Mn in alpha-Fe2O3 and growing sequence of Mn doped alpha-Fe2O3 (Mn:Fe2O3) and Ti doped alpha-Fe2O3 (Ti:Fe2O3) are also investigated to illustrate the efficient design of Mn:Fe2O3/Ti:Fe2O3 homojunction. The optimized Mn:Fe2O3/Ti:Fe2O3 electrode shows the highest photocurrent density of 2.10 mA/cm(2) at 1.60 VRHE respectively comparing to those of 0.10, 1.20 and 0.22 mA/cm(2) for Ti:FeOOH, Ti:Fe2O3 and alpha-Fe2O3 electrodes. The outstanding performance of Mn:Fe2O3/Ti:Fe2O3 homojunction is attributed to the smaller charge transfer resistance, higher carrier density, and less charge recombination. This work gives a rational design for hematite -based photocatalysts and successfully attains greatly improved photocatalytic ability for water oxidation. Development of homojunction using heteroatom doping in thus verified to be highly applicable on synthesizing promising photocatalysts. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.