Photocatalytic H 2 O 2 generation using unlimited solar energy for in situ oxidation of organic pollutants in wastewater has been environmentally attractive. Photocatalytic H 2 O-to-H 2 O 2(aq) reaction by BiVO 4 , however, suffered from relatively low yields (e.g., 24 μM h −1 ) under visible-light irradiation, mainly due to its high recombination rate of charge carriers. Herein, nanostructured NiCo 2 O 4 /BiVO 4 Z-scheme heterojunctions were prepared to increase the oxygen reduction reaction for a higher H 2 O 2 yield rate (than BiVO 4 by 16 times approximately). Additionally, highly reactive superoxide ( • O 2 − ) and hydroxyl ( • OH) radicals from the photocatalytic H 2 O-to-H 2 O 2 process enhanced oxidation of a representative organic pollutant (i.e., methylene blue) under visiblelight irradiation. The photocatalytic oxidation rate constant was as high as 2 × 10 −7 M −1 s −1 . This visible-light photocatalytic H 2 O-to-H 2 O 2 synchronized oxidation of an organic pollutant by the nanostructured NiCo 2 O 4 /BiVO 4 heterojunctions demonstrates the possibility for a potential energy self-sufficient organic wastewater treatment process.
Photocatalytic H2O-to-H2(g) and -H2O2(aq) (2H2O(l) →H2(g) + H2O2(aq)) through a two-electron reaction is kinetically feasible. The proton-coupled two-electron transfer induced photocatalytic oxygen reduction reaction (ORR) from oxygen and water is...
A photocatalytic
H
2
O-to-H
2
O
2
reaction
for sustainable organic wastewater treatment is environmentally attractive.
Phenolic resins, inexpensive metal-free photocatalysts, are capable
of harvesting visible light. Herein, novel nitrogen-enriched resin
photocatalysts with a desired band-gap energy (1.83–1.98 eV)
for harvesting visible light were prepared by copolymerization of
resorcinol and melem for simultaneous photocatalytic H
2
O-to-H
2
O
2
and oxidation of methylene blue.
Under visible light irradiation for 5 h, very high yields of H
2
O
2
(870–975 μM of H
2
O
2
/g/h) by RFM resin photocatalysts could be achieved. The photocatalytic
H
2
O
2
for reactive oxygen species (
•
OH) and photogenerated h
+
could account for high conversion
(40% conversion under visible light irradiation within 3 h) in oxidation
of methylene blue. Such unique low-cost metal-free resins demonstrate
the visible light photocatalytic H
2
O-to-H
2
O
2
reaction which can synergize with the oxidation of organic
pollutants in wastewater.
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