Advances towards the utilization of Vis-NIR light energy by coating YF3:Yb3+,Er3+ over ZnS microspheres triggering hydrogen production and pollutants disposal

Abstract

Harvesting abundant and environmentally friendly near infrared (NIR) light in the solar spectrum is particularly significant to improve the utilization of the cleanest energy on the earth. One of the most effective methods to improve the photocatalytic efficiency of semiconductors in the full-solar spectrum is combining upconversion luminescence materials with semiconductors. In this work, a novel ZnS@YF₃:Yb³⁺,Er³⁺ heterojunction as a full spectrum photocatalyst via a hydrothermal synthesis method is reported, which was applied in hydrogen production and pollutants disposal. Under metal halide lamp irradiation with UV-Vis-NIR light, ZnS@YF₃:Yb³⁺,Er³⁺ exhibited higher photocatalytic performance compared to pure ZnS. In addition, the 20% YF₃:Yb³⁺,Er³⁺/ZnS sample showed the highest chemical stability and strongest reduction ability. This was mainly attributed to the effective fluorescence resonance energy transfer of YF₃:Yb³⁺,Er³⁺/ZnS, the broader light absorption and the efficient transfer of photoinduced electrons. Moreover, the ˙O₂⁻ and ˙OH free radicals were the main reactive species. This study suggests a promising system to efficiently utilize the visible-NIR solar energy of sunlight for processing industrial waste water and alleviating the energy crisis in the future.