Decorating Ag3PO4 Nanodots on Mesoporous Silica-functionalized NaYF4:Yb,Tm@NaLuF4 for Efficient Sunlight-driven Photocatalysis: Synergy of Broad Spectrum Absorption and Pollutant Adsorption-Enrichment
Efficiently harvesting solar energy for photocatalysis remains a challenge because near infrared (NIR) light with low excitation energy cannot be directly utilized by general semiconductor photocatalysts, although it makes up 46% in solar spectrum. Herein, a broad-spectrum photocatalyst with pollutant adsorption-enrichment capability to enable a natural sunlight-driven photocatalysis was synthesized by decorating a small amount of silver orthophosphate (Ag3PO4) nanodots on mesoporous silica (mSiO2) functionalized upconversion nanoparticles (UCNPs; NaYF4:Yb,Tm@NaLuF4). The UCNPs play a role of broadening the absorption spectrum by upconverting the NIR light into the visible light, which is absorbable by Ag3PO4 nanodots. The functionalized hydrophilic mSiO2 shell not only facilitates the decoration of Ag3PO4 nanodots but also is capable of adsorbing and enriching pollutants around Ag3PO4 nanodots to enhance photoactivity. Upon natural sunlight irradiation, the as-prepared photocatalyst (UCNP@mSiO2-Ag3PO4) exhibits a remarkable photoactivity with degradation rate constants of 0.24 and 0.051 min−1 under stirring and static conditions respectively, exceeding the pure Ag3PO4 sample by factors of 4.2 and 12.5. It can be anticipated that design of photocatalysts with the synergy of broadband absorption and pollutant adsorption-enrichment can be a promising strategy to realize an efficient sunlight-driven photocatalysis, even without extra mechanic stirring for future scale-up water treatment.