Unraveling the Mechanism on Ultrahigh Efficiency Photocatalytic H₂O₂ Generation for Dual‐Heteroatom Incorporated Polymeric Carbon Nitride

Abstract

Photocatalytic hydrogen peroxide (H 2 O 2 ) production from dioxygen and water is regarded as a promising technology since it can achieve sustainable and green solar-to-chemical energy conversion. Herein, oxygen and potassium dual-heteroatom incorporated polymeric carbon nitride (O/KCN) is rationally designed for H 2 O 2 generation with an ultrahigh rate of 309.44 µM h −1 mg −1 , which surpasses that of other C 3 N 4 -based photocatalysts. The enhanced performance can be ascribed to the effective light absorption, fast charge transfer/separation, strong oxygen adsorption, and highly selective twoelectron oxygen reduction reaction (ORR). Density functional theory calculations further confirm that the obtained O/KCN is more favorable than others for electrons migrating from β spin-orbital to π* orbitals of O 2 molecule, thus optimizing O 2 molecule activation to promote the formation of intermediate species *OOH and decrease the energy barrier of H 2 O 2 production. This work not only provides in-depth insights for the photocatalytic H 2 O 2 generation mechanism, but also lays the foundation for further development of highly active photocatalysts for environmental remediation and energy conversion.

Iodide ions as invisible chemical scissors tailoring carbon nitride for highly efficient photocatalytic H2O2 evolution

“…7b). 49 Obviously, compared with BCN and TCN, the negative charges of BCN/NaI 0.4 and TCN/NaI 0.4 are relatively stable in the whole pH range (3)(4)(5)(6)(7)(8)(9)(10)(11), and no point of zero charge appears. In addition, the specific surface areas were recorded using N 2 adsorption/desorption isotherms (Fig.…”

“…Graphitic carbon nitride (g-C 3 N 4 ) has attracted much attention and is considered an ideal photocatalyst for H 2 O 2 production due to its high stability, easy fabrication, low-cost components and appropriate band structure. 10 Despite some of the above advantages, problems like low selectivity of the two-electron (2e − ) oxygen reduction reaction (ORR), inferior O 2 adsorption ability, low specific area and rapid charge carrier recombination still exist in pristine g-C 3 N 4 . 11 Up to now, lots of methods have already been proposed to enhance the photocatalytic performance of g-C 3 N 4 for H 2 O 2 production, including heterojunction construction, 12 nanostructure tailoring, 13 co-catalyst loading 14 and defect or doping modifications.…”

Sequencing batch photocatalytic H2O2 production over a magnetic resorcinol–formaldehyde polymer for on-site water purification by UV light irradiation

“…When the suspension is purged by O 2 , the dissolved O 2 increases to about 40 mg/L, and the photocatalytic H 2 O 2production within 60 min is enhanced to 150 μM. However, when purging with N 2 , the system produces negligible H 2 O 2 , suggesting oxygen reduction is the main pathway for H 2 O 2 production[49][50][51] . Upon a 12-hour irradiation under air purging condition, MRF can produce 1200 μM H 2 O 2 without any retardation (FigureS3), which is a relatively high value in the systems of photocatalytic H 2 O 2 production in the absence of any organic sacrificial agent (TableS1).The ratios of RF to Fe 3 O 4 @SiO 2 in MRF are optimized by measuring the performance of photocatalytic H 2 O 2 production.…”

Recent Advances in g-C3N4-Based Donor–Acceptor Photocatalysts for Photocatalytic Hydrogen Evolution: An Exquisite Molecular Structure Engineering

“…90 Moreover, the high PCCs recombination rate and limited light response of primal CN also severely constrain its photocatalytic performance. 91,92 The design of DA-CN photocatalysts is a productive approach to get over the intrinsic limitation of primal CN. Owing to the created built-in electric field, the interfacial heterojunction formed by adding conductive organic polymers (COPs) may considerably promote the spatial separation of PCCs while simultaneously improving the conductivity of photocatalysts.…”

“…Additionally, the specific surface area of primal CN is generally low because of the layer stack . Moreover, the high PCCs recombination rate and limited light response of primal CN also severely constrain its photocatalytic performance. , …”