Au Nanoparticles coupled Three-dimensional Macroporous BiVO4/SnO2 Inverse Opal Heterostructure For Efficient Photoelectrochemical Water Splitting

We demonstrated a strategy for coupling Au nanoparticles with ordered inverse opal heterostructure (Au-BiVO4/SnO2 IO) via a novel template-assisted, swell-to-shrink, hydrothermal method. The synergistic function of surface plasmon resonance (SPR) effect of Au nanoparticles and slow photon effect of inverse opal structure on photoelectrochemical water splitting performance of Au-BiVO4/SnO2 IO is investigated. The Au-BiVO4/SnO2 IO shows enhanced light absorption ability in visible region and suppressed recombination of photogenerated electron-hole pairs. The inverse opal structure enables light to bounce and scatter between the highly ordered tunnels, leading to efficient light harvesting. By overlapping the slow photon effect of inverse opal, the SPR effect is effectively amplified, leading to a more striking enhancement in light utilization. The Au-BiVO4/SnO2 IO displays a photocurrent density of 3.83 mA cm−2 and an IPCE of 70.8% at 1.23 V vs. RHE, more than 3 times higher than planar BiVO4. The improved photoelectrochemical performance is attributed to two aspects: one is the enhanced light harvesting from the coupling between the slow light and SPR effect, the other is the efficient separation of charge carriers owing to the Schottky barriers. The work provides promising strategies for designing plasmon coupled inverse opal semiconductor photoelectrodes to synergistically enhance PEC performance.