Affiliation:
1. Nanyang Technological University
2. Shenzhen University
3. Kyushu Institute of Technology
4. nsrrc
5. Okayama University
6. City University of Hong Kong
7. The Third Affiliated Hospital of Soochow University
8. Yangzhou University
Abstract
AbstractProviding affordable safe drinking water and universal sanitation poses a grand challenge especially after the global COVID-19 pandemic. In this work, we developed atomically dispersed Au on potassium-incorporated polymeric carbon nitride (AuKPCN) that could simultaneously boost photocatalytic generation of ·OH and H2O2with an apparent quantum efficiency over 90% at 400–420 nm. The introduction of potassium into the poly(heptazine imide) matrix formed strong K-N bonds, preventing Au from forming strong interactions with N. Instead, Au formed a bond with C, only having weak interactions with N on KPCN, which rendered Au with an oxidation number close to 0. The results ofin-situvibrational spectroscopy, isotopic experiments, transient absorption spectroscopy and time-dependent density functional theory (TDDFT) simulations revealed that the low-valent Au could append its 6s orbital into the band diagram of AuKPCN that formed a trapping level for generating highly localized holes under photoexcitation. These highly localized holes could boost the 1e−water oxidation reaction to form highly oxidative ·OH and simultaneously unbind the hydrogen atom in H2O molecule, which greatly promoted the hydrogenation process during the 2e−oxygen reduction reaction (ORR) to produce H2O2. The photogenerated ·OH on AuKPCN led to a more than 120-fold efficiency enhancement for visible-light-response superhydrophilicity as compared to that of the commercial TiO2. The onsite fixed-bed reactor under photo-illumination achieved a remarkable 132.5 LH2Om− 2day− 1water disinfection rate (lg6), which is about 30 times superior than the TiO2photocatalytic advanced oxidation process in the most ideal case (< 4 LH2Om− 2day− 1; lg4).
Publisher
Research Square Platform LLC
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