Ni Foam Supported TiO2 Nanorod Arrays with CdS Branches: Type II and Z-Scheme Mechanisms Coexisted Monolithic Catalyst Film for Improved Photocatalytic H2 Production

TiO2 has garnered a flourish of interest in the field of energy storage and energy conversion. Herein, a new generation of 3D Ni foam supported in situ grown 1D TiO2 nanoarray (Ni/TiO2) is successfully prepared, through an easy solution-phase hydrothermal process, and then CdS nanorods branched Ni/TiO2 nanoarrays are fabricated (Ni/TiO2 (R) CdS). Their formation parameters and growth mechanism are carefully studied. Both Ni/TiO2 and Ni/TiO2 (R) CdS monolithic catalysts exhibit advantaged photocatalytic (PC) and photoelectrocatalytic (PEC) water splitting properties compared with that of most previously reported TiO2-based film photocatalysts. Mechanism investigation reveals that both type II and Z-scheme charge transport mechanisms coexist in Ni/TiO2 (R) CdS sample, and an additional Z-scheme charge transfer effect accelerates the photogenerated charge separation and transport efficiency. This study may open a new avenue for the utilization of TiO2 -based film catalysts in a broader field of energy and environmental catalysis areas.

Automated summary

This study successfully prepared a new generation of Ni/TiO2 and Ni/TiO2 (R) CdS monolithic catalysts and found that their photocatalytic and photoelectrocatalytic water splitting properties are superior to previously reported TiO2-based film photocatalysts. Mechanism investigation revealed the coexistence of Z-scheme and type II charge transport mechanisms and their impact on the efficiency of photogenerated charge separation and transport.