Synergistic Cu single-atoms and clusters on tubular carbon nitride for efficient photocatalytic performances

Metal clusters or even single-atoms dispersed and anchored on the photocatalysts’ surface can enhance photocatalytic performances on organic pollutant oxidation. Here, a simple photoreduction method was used to create atomically dispersed metal single-atoms/clusters (MSCs, M = Cu, Pd, Au and Ag) on P-modulated tubular carbon nitride (TCN). The obtained MSCs@TCN demonstrated excellent photocatalytic performances for the degradation of sulfamethazine (SMZ). In particular, the photocatalyst with 2 wt% Cu loading showed ultrahigh SMZ oxidation efficiency (k = 0.06110 min⁻¹), almost three times that of TCN (k = 0.02066 min⁻¹). It also shows excellent stability in the 5th-cycle measurements. The improved photocatalytic activity of the CuSCs@TCN is ascribed to the synergistic promotion of photogenerated charge separation by Cu single-atoms/clusters as active sites, accelerated charge transfer from bulk TCN to Cu sites through Cu–N_x interaction. Meanwhile, the active sites of Cu single-atoms/clusters could promote the production of ·O₂⁻, which participates in organic oxidation with strong oxidizing holes (h⁺). This strategy paves a new avenue for designing high-performance photocatalysts decorated with metal single-atoms and clusters.