title: The effect of crystallinity on photocatalytic performance of Co3O4 water-splitting cocatalysts.
abstract: Cocatalysts, when loaded onto a water splitting photocatalyst, accelerate the gas evolution reaction and improve the efficiency of the photocatalyst. In this paper, we report that the efficiency of the photocatalyst is enhanced using an amorphous cobalt oxide cocatalyst. The WO3 film, when loaded with amorphous or nanocrystalline Co3O4, shows an improvement of up to 40% in photocurrent generation and 34% in hydrogen gas evolution. The effect of cocatalyst crystallinity on performance was systematically studied, and we found that the photocurrent deteriorates with the conversion of the cocatalyst to a highly crystalline phase at an annealing temperature of 500 °C. The mechanism of this effect was studied in detail using electrochemical impedance spectroscopy, and the enhancement effect produced by the amorphous cocatalyst is attributed to the large density of unsaturated catalytically active sites in the amorphous material.
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg.
authors.forename: Chin Sheng
authors.initials: CS
authors.lastname: Chua
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg and School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Davide
authors.initials: D
authors.lastname: Ansovini
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg.
authors.forename: Coryl Jing Jun
authors.initials: CJ
authors.lastname: Lee
authors.affiliation: Energy Research Institute @NTU (ERI@N), Research Techno Plaza, X-Frontier Block, Level 5, 50 Nanyang Drive, Singapore 637553, Singapore.
authors.forename: Yin Ting
authors.initials: YT
authors.lastname: Teng
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg.
authors.forename: Lay Ting
authors.initials: LT
authors.lastname: Ong
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg.
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Chi
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg and Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
authors.forename: T S Andy
authors.initials: TS
authors.lastname: Hor
authors.affiliation: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Raja
authors.affiliation: Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore. limyf@imre.a-star.edu.sg.
authors.forename: Yee-Fun
authors.initials: YF
authors.lastname: Lim