CsPbBr₃ Perovskite Quantum Dots Photoanode For Water Splitting

The shortage of traditional fossil fuels and the growing global environmental problems are forcing people to develop renewable and clean energy sources.Hydrogen,as an ideal clean energy source with no carbon and high energy density,is expected to replace traditional fossil energy sources and become an important part of future energy development.However,traditional hydrogen production methods still have certain environmental pollution problems.In order to achieve completely clean and pollution-free hydrogen production,solar energy as another clean energy source,using solar photocatalytic splitting of water is one of the most ideal ways inside all hydrogen production methods.Meanwhile,all-inorganic perovskite CsPbBr₃ quantum dots（CsPbBr₃ QDs）are ideal materials for the preparation of efficient solar hydrogen production catalysts due to their high absorption coefficient,high carrier mobility and their unique quantum-limited effect as quasi-zero-dimensional materials.However,its water stability further leads to a series of problems such as poor photocatalytic activity,which seriously limits its application in the field of photocatalytic decomposition of water.Therefore,in order to effectively solve the above problems,this paper investigates the modification of CsPbBr₃ QDs and their photoanode devices by ion doping,interfacial passivation,ligand substitution and other modification methods.The main contents include the following:Starting from the internal structure of the crystal,the CsPbBr₃ QDs were ion-doped with cobalt to partially replace the Pb sites with Co,which improved the energy band structure of the quantum dots and enhanced their binding energy.By lowering the carrier transport barrier,the separation and transport efficiency of photogenerated carriers are further enhanced,and the carrier concentration is increased,which in turn improves their photocatalytic activity.The photocurrent density of 1.944 m A/cm² was achieved at 1.23V_RHE under simulated sunlight（AM 1.5 G,100 m W/cm²）irradiation,with a 4.61-fold improvement in performance.And the stable operation time in aqueous system reached5500 s.Meanwhile,the theoretical hydrogen production rate reached 3.12μmol·cm^-2·h^-1.Starting from the device structure optimization,the interface between the Ti O₂electron transport layer and the CsPbBr₃ photosensitive layer was passivated using a CsPb interfacial passivator to improve the Ti O₂/CsBr layer energy band structure,which is conducive to the inhibition of photogenerated carrier complexation and the improvement of the separation and transport efficiency of photogenerated electron-hole pairs,thus improving the Ti O₂/CsBr/CsPbBr₃ QDs photoanode device photocatalytic decomposition activity of water.The photoelectric device produced a photocurrent density of up to 3.343m A/cm² at 1.23 V_RHE,a 6.17-fold improvement in performance,and a theoretical hydrogen production rate of 3.69μmol·cm^-2·h^-1.Starting from the grain spacing,ligand engineering was employed to partially replace the oleic acid ligand on CsPbBr₃ QDs with 3-mercaptopropionic acid ligand,which enhanced the photocatalytic activity by shortening the mutual distance between the quantum dot grains to enhance their electrical conductivity while greatly improving the separation and transport efficiency of the surface photogenerated electron-hole pairs.In addition,the dense arrangement between quantum dots further improves the water stability of its photoanode device,which shows a photocurrent density of 4.394 m A/cm²at 1.23 V_RHE,an 8.11-fold improvement in performance,and a stable operating time of up to 11,600 s in the aqueous system with a theoretical hydrogen production rate of up to6.336μmol·cm^-2·h^-1.