A CdS/rGO QDs/TiO2 nanolawn photoanode co-decorated with reduced graphene oxide quantum dots and CdS nanoparticles with photoinduced cathodic protection characteristics of 316L SS and Cu

Abstract

Clean and sustainable photoelectric technology has been developed rapidly in many fields. One of which is the novel marine corrosion protection technology that directly utilizes the abundant solar energy falling on the ocean to provide photoinduced cathodic protection for metallic structures, and has received increasing attention year by year. Improving the photoelectrochemical conversion and photoelectric cathodic protection performance for metals under sunlight is vital for achieving effective protection. In particular, optimizing the multi-dimensional nanostructured photoanode to accelerate the collection and transfer of photogenerated electrons and to improve the photoelectric and cathodic protection performance is a promising method. Here, an ultrafine branched anatase TiO₂ nanolawn (NL) photoanode co-decorated with CdS nanoparticles and reduced graphene oxide quantum dots (rGO QDs) was prepared. Compared with single CdS modified TiO₂ NL, the three-phase junction CdS/rGO QDs/TiO₂ NL shows further enhanced photoelectrochemical conversion performance under simulated sunlight and visible light irradiation, increased by 66.7% and 83.3% compared to that of CdS/TiO₂ NL, respectively. The rGO QDs, which acted as a high-efficiency electron transporter, are uniformly deposited on the TiO₂ NL, and further promote the transport efficiency of photogenerated electrons. CdS as a visible-light responder is responsible for broadening the spectral response, and the ultrafine branched TiO₂ NL substrate greatly expands the photon capture area and increases the electron collection sites. Finally, the synergy of the above three aspects ensures that the ternary CdS/rGO QDs/TiO₂ NL photoanode exhibits further enhanced simulated sunlight-driven and visible light-driven photoelectric conversion efficiency and a photoinduced cathodic protection effect on 316L stainless steel and pure copper.