Modulated Solution Plasma Environment over Modified-C 3 N 4 /TCPP Polymers for Sustainable H 2 O 2 Production

Nonmetallic polymers are promising materials for the production of H 2 O 2 by O 2 reduction reactions in water, since they activate oxygen to reactive oxygen species under photo/electrical excitation. However, the slow kinetics of water activation restricts the rate of H 2 O 2 production. Solution plasma technology has emerged as a promising strategy, as it effectively activates water molecules, thereby facilitating the water oxidation process while simultaneously introducing an oxygen reduction pathway that consumes H + ions for efficient H 2 O 2 production. Here, we loaded meso-tetra(4-carboxyphenyl) porphyrin (TCPP) with photosensitizing properties onto cyano-modified carbon nitride (CCN) to form π–π-stacked solution plasma catalysts that exhibited excellent H 2 O 2 activity. The H + concentration in the CCN/TCPP polymer solution decreased by a factor of 10 4 after 1 h of discharge compared to the noncatalyst system, indicating that the catalyst promoted the O 2 reduction reaction. The CCN/TCPP accumulated 32 mM H 2 O 2 with an energy conversion efficiency of 0.91%. The lower intersystem crossing (ISC) energy barrier of CCN/TCPP allows CCN/TCPP and O 2 to produce 1 O 2 at a faster energy transfer rate to consume H + from the discharge and produce H 2 O 2 . This study widens the design of solution plasma catalysts for the production of H 2 O 2 and provides an effective strategy for the sustainable development of solution plasma catalytic technology.