Focusing on the photo-thermochemical water splitting hydrogen production technology

where photoreaction and thermal reaction are carried out sequentially

the CeO_2 synthesized by sol-gel method and its metal-doped catalysts were taken as the research objects to carry out experimental tests

through which the effects of photoreaction in generating oxygen vacancies and thermal reaction in hydrogen production were investigated.During the photoreaction

CeO_2 catalysts doped with three elements(Fe

Cu

Zn) at three different ratios(5%

10%

15%) were used. The metal-doped catalysts were characterized by several methods

such as X-ray diffraction(XRD)

transmission electron microscopy(TEM)

electron paramagnetic resonance(EPR)

photoluminescence(PL)

ultraviolet visible diffuse reflectance spectroscopy(UV-Vis DRS)

inductively coupled plasma(ICP)

and BET specific surface area testing method. The results indicate that

the 10% Cu-doped CeO_2 catalyst exhibits the best photothermal hydrogen production performance. This is attributed to the smallest size of Cu nanoparticles

which results in the smallest bandgap width for the Cu-doped CeO_2 catalyst. Consequently

it can absorb higher energy photons

enhancing the light absorption capacity

and improving the separation and recombination rates of photogenerated charge carriers. This facilitates the formation of photogenerated oxygen vacancies

thereby enhances the hydrogen production capability during the thermal reaction process.