The g-C ₃ N ₄ with dual defect sites exhibits excellent photocatalytic H ₂ O ₂ generation activity and selectivity, and the key role of each defect site in the surface reaction mechanism is revealed.

The increased number of carrier pockets near the Fermi level and the optimized carrier concentration in doped SnSe single crystal can lead to a high average ZT _ave ∼ 1.2 from 300 K to 800 K and a peak ZT _max value in excess of 2.0 at 800 K along the crystallographic b -axis.

A new all-in-one design concept of constructing photochromic single atom photocatalysts is proposed to achieve both high activity and selectivity of photocatalytic CO₂-to-CH₄ conversion.