Enhanced charge transfer kinetics of Fe2O3/CdS composite nanorod arrays using cobalt-phosphate as cocatalyst

Photoelectrochemical (PEC) water splitting is one of the most efficient strategies to meet the challenges of the global energy crisis. Although hematite (alpha-Fe2O3), is a suitable material for PEC, its performance is limited by passive surface state and slow charge transfer kinetics. Here, a successful design and fabrication of novel ternary Fe(2)O(3)3/CdS/Co-Pi nanorod arrays (NRAs) photoanode is reported aimed at boosting charge separation and transfer kinetics within the bulk and at the electrode/electrolyte interface. As expected, the results reveal that alpha-Fe2O3 sluggish reaction kinetics is greatly ameliorated upon depositing CdS and Co-Pi, and surface charge recombination decreases even more, resulting in substantially enhanced photocurrent density. Moreover, noticeable onset potential negative shift evidenced by the I-V curve is found to result from the deposition of CdS and Co-Pi, which allows the ternary composite to generate photocurrent at much lower applied potential. We elaborate the synergistic effect of CdS and Co-Pi in achieving faster charge transfer kinetics and lower onset potential for photocurrent. These results provide new insights into the surface reaction kinetics of Co-Pi/semiconductor photoanode toward PEC application. (C) 2017 Elsevier B.V. All rights reserved.