421825 On the Origin of Enhanced Surface Reaction Kinetics and Charge Separation for p-n Hheterojunction on Co3O4/BiVO4 Photoanodes

Wednesday, November 11, 2015
Exhibit Hall 1 (Salt Palace Convention Center)
Xiaoxia Chang, Tuo Wang and Jinlong Gong, Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China

Surface reaction kinetics and bulk charge separation are both critical to the efficiency of solar water splitting. In addition to the well documented surface catalytic effect, the promotion of bulk charge separation upon the loading of cocatalysts has rarely been reported. This talk describes the synergetic enhancement of surface reaction kinetics and bulk charge separation by introducing discrete nano-island p-type Co3O4 cocatalysts onto n-type BiVO4, forming p-n Co3O4/BiVO4 heterojunction with internal electric field to facilitate charge transport. Being highly dispersed on the surface of photoanodes, the nano-island cocatalysts could suppress the formation of recombination centers at the photoanode/cocatalyst interface. This cocatalyst loading method achieved a charge separation efficiency of up to 77% in the bulk and 47% on the surface of catalysts. An AM 1.5 photocurrent of 2.71 mA/cm2 at 1.23 V versus the reversible hydrogen electrode for water oxidation was obtained, which is the highest photocurrent yet reported for cobalt catalyzed undoped BiVO4 photoanodes, with a photoconversion efficiency of 0.659%.

Extended Abstract: File Uploaded