Mechanistic analysis of multiple processes controlling solar-driven H2O2 synthesis using engineered polymeric carbon nitride

Abstract

Solar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride framework with sodium cyanaminate moiety, affording a H2O2 production rate of 18.7 μmol h −1 mg−1 and an apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed, and some previously unknown structural features and interactions are substantiated via experimental and theoretical methods. The structural features of cyanamino group and pyridinic nitrogen-coordinated soidum in the framework promote photon absorption, alter the energy landscape of the framework and improve charge separation efficiency, enhance surface adsorption of dioxygen, and create selective 2e− oxygen reduction reaction surface-active sites. Particularly, an electronic coupling interaction between O2 and surface, which boosts the population and prolongs the lifetime of the active shallow-trapped electrons, is experimentally substantiated.

Synergistic Modulation of the Separation of Photo‐Generated Carriers via Engineering of Dual Atomic Sites for Promoting Photocatalytic Performance

“…1 H-NMR results also confirmed the formation of DFF during the photocatalytic reaction (FigureS24, Supporting Information). Cycle tests were performed to investigate the stability of Cu SAs/p-CNS.…”

“…Polymeric carbon nitride (p‐CN) as a common semiconductor photocatalyst has received considerable attention for application in photocatalytic systems due to its low‐cost precursors and excellent chemical stability. [ 1 ] However, the application of p‐CN is restricted by the low separation and transfer efficiency of photo‐generated carriers. To address these issues, many research groups have employed a variety of approaches to modify bulk p‐CN, for instance, doping hetero‐elements, formation of composites, and construction of multi‐component hetero‐nanostructures, to circumvent the challenge of charge transfer and hence to improve the photocatalytic performance.…”

A bioinspired hollow g-C3N4–CuPc heterostructure with remarkable SERS enhancement and photosynthesis-mimicking properties for theranostic applications

“…1I ) indicates fast luminescence quenching of HCNCs, which might be attributed to the fact that charge separation is enhanced by extended π-conjugated systems and delocalization of the π-electrons after the CuPc conjugation. 34 This suggests additional decay pathways for the photoexcitation, by which the CT process is expected to improve the SERS performance and photosynthesis-mimicking activity.…”

1,4,5,8-Naphthalene tetracarboxylate dianhydride/g-C3N4 van der Waals heterojunctions exhibit enhanced photochemical H2O2 production and antimicrobial activity

“… 43,44 The resulting non-emissive, surface-trapped electrons have the potential to promote the desired oxygen reduction reactions at the photocatalyst surface. 45 The rate of injection of electrons ( k CT ) from CN to NTCDA was calculated according to eqn (2) and is 6.70 × 10 7 s −1 . This value compares extremely favorably to electron transfer rates reported for other CN-based materials.…”

“…To experimentally validate the results of the PL and TCSPC analysis described above, we irradiated samples of the 5N/CN heterojunction under an inert atmosphere in the presence of the hole scavenging agent glycerol. Deposition of NTCDA on the surface of CN promotes accumulation of photoelectrons, as illustrated by the formation of a characteristic blue-green color in the irradiated sample 45,47 (ESI, Fig. S6 † ).…”