Ag/TiO2 catalyst with fine size and homogeneous dispersion of coated silver clusters was synthesized by a recently developed pHcontrolled photocatalytic process and applied to the photocatalytic reduction of nitrate as an environmentally friendly and low-cost catalyst
with formic acid as a hole scavenger. Compared with conventional preparation routes, the as-prepared Ag/TiO2catalyst in this study shows
better catalytic performance: a nitrate conversion of 98% and selectivity for nitrogen of ca. 100%, which can be achieved after 30 min of
irradiation. The average activity was calculated to be ca. 24 mmolNO3
−g
−1
Ag
min−1
, which is much higher than that of most of Pd–Cubased nitrate hydrogenation systems in terms of metal usage, demonstrating its application potential. A similar photocatalytic efficiency
and selectivity for nitrogen were also observed for nitrite photocatalytic reduction on this catalyst. The effects of Ag content, hole scavengers, concentration of formic acid, and other anions present in drinking water, such as SO4
2−
,CO3
2−
,andHCO3
−
, were systematically
investigated.