Abstract
ABSTRACT
Sunlight‐driven conversion of NO
3
−
‐to‐NH
3
holds immense significance for fostering a green and sustainable society. However, most of the existing photocatalysts have weak light absorption and a wide band gap, making the synthesis of NH
3
challenging on a large scale under sunlight. Herein, a photocatalyst Fe
3+
1‐x
Fe
2+
x
OOH/CdSeS that was in situ formed from MPA‐CdSe QDs and transition metal ions (i.e., Fe
3
+
used here) under visible light irradiation at room temperature, accomplished a gram‐scale synthesis of NH
3
in a 625 cm
2
plate‐type reactor. Under sunlight, 177.18 mmol NH
3
was synthesized, and 7.83 g of NH
4
Cl solid was collected after five cycles totaling 115 h, and the solar‐to‐ammonia (STA) was 0.664%. Experimental characterization and density functional theory (DFT) calculations reveal that the formation of Fe
3+
1‐x
Fe
2+
x
OOH/CdSeS nanostructures is the key to the exceptional activity. The reversible Fe
3+
/Fe
2+
redox cycling within the clusters facilitates charge separation and interfacial transfer from CdSeS QDs to Fe
3+
1‐x
Fe
2+
x
OOH under irradiation, while oxygen vacancies in Fe
3+
1‐x
Fe
2+
x
OOH clusters bind NO
3
−
for subsequent NH
3
formation. The apparent quantum yield is 15.89% ± 1.75% at 436 nm, and the yield of NH
3
is 522.47 mmol g
cat
−1
h
−1
based on Fe
3+
1‐x
Fe
2+
x
OOH/CdSeS photocatalyst, a 5.82‐fold enhancement over the reported record of 89.79 mmol g
cat
−1
h
−1
, demonstrating remarkable application potential for sunlight‐driven NO
3
−
reduction to NH
3
.