Ceria-based quantum dots/nanorods supported metallic cobalt for efficient photocatalytic hydrogen production

The concentration of photogenerated electrons on support surface has a significant impact on the photocatalytic performance of the corresponding catalyst. Herein, the CeO2-based homojunction support consisted of quantum dots/nanorods (QDs/NRs) was fabricated by two-step calcination with assistance of KCI and NaCl. Based on CeO2-QDs/NRs support, the Co-based catalyst exhibited excellent catalytic performance for photocatalytic hydrogen evolution from Ammonia Borane (NH3BH3). The catalysts exhibited the highest activity with TOF 96.15 min−1 under optimized conditions, which was significantly improved compared Co/CeO2 NRs (68.5 min−1). Detailed structure characterizations revealed that the QDs with size range from 2 to 5 nm grow on the surface of NRs, which had capacity to transfer more photogenerated electrons from the bulk to surface compared with pristine CeO2 NRs. Meanwhile, work function was upshifted from CeO2 NRs to CeO2-QDs/NRs. The synergy of two factors drove more electrons transfer from CeO2-QDs/NRs to active metal Co, accelerating the adsorption and activation of NH3BH3. In addition, the forming mechanization QDs by inducing the morphological evolution of CeO2 nanoparticles was also investigated. This work not only provides efficient photocatalyst for H2 evolution from NH3BH3 but also provides new insights into the design and preparation efficient QDs-based homojunction catalyst.