Polymeric carbon nitride (PCN) as ac lass of twoelectron oxygen reduction reaction (2 e À ORR) photocatalyst has attracted much attention for H 2 O 2 production. However, the low activity and inferior selectivity of 2e À ORR greatly restrict the H 2 O 2 production efficiency.H erein, we develop an ew strategy to synthesize hydrophilic, fragmented PCN photocatalyst by the terminating polymerization (TP-PCN) effect of iodide ions.T he obtained TP-PCN with abundant edge active sites (AEASs), which can form quasi-homogeneous photocatalytic system, exhibits superior H 2 O 2 generation rate (3265.4 mMh À1 ), far surpassing PCN and other PCNbased photocatalysts.D FT calculations further indicate that TP-PCN is more favorable for electron transiting from b spinorbital to the p*orbitals of O 2 ,which optimizes O 2 activation and reduces the energy barrier of H 2 O 2 formation. This work provides anew concept for designing functional photocatalysts and understanding the mechanism of O 2 activation in ORR for H 2 O 2 production.

A further understanding of the structure of lignin from herbaceous crops is needed for advancing technologies of lignocellulosic biomass processing and utilization. A method was established in this study for analyzing structural motifs found in milled straw lignin (MSL) and cellulase-digested lignin (CEL) isolated from wheat straw by combining quantitative (13)C and HSQC NMR spectral analyses. The results showed that guaiacyl (G) was the predominant unit in wheat straw cell wall lignin over syringyl (S) and hydroxyphenyl (H) units. Up to 8.0 units of tricin were also detected in wheat straw lignin per 100 aromatic rings. Various interunit linkages, including β-O-4, β-5, β-β', β-1, α, β-diaryl ether, and 5-5'/4-O-β' as well as potential lignin-carbohydrate complex (LCC) bonds, were identified and quantified. These findings provide useful information for the development of biofuels and lignin-based materials.

The piezo‐assisted photocatalysis system, which can utilize solar energy and mechanical energy simulteneously, is promising but still challenging in the environmental remediation field. In this work, a novel metal–semiconductor BaTiO3@ReS2 Schottky heterostructure is designed and it shows high‐efficiency on piezo‐assisted photocatalytic molecular oxygen activation. By combining experiment and calculation results, the distorted metal‐phase ReS2 nanosheets are found to be closely anchored on the surface of the BaTiO3 nanorods, through interfacial ReO covalent bonds. The Schottky heterostructure not only forms electron‐transfer channels but also exhibits enhanced oxygen activation capacity, which are helpful to produce more superoxide radicals. The polarization field induced by the piezoelectric BaTiO3 can lower the Schottky barrier and thus reduce the transfer resistance of photogenerated electrons directing to the ReS2. As a result of the synergy effect between the two components, the BaTiO3@ReS2 exhibits untrahigh activity for degradation of pollutants with an apparent rate constant of 0.133 min−1 for piezo‐assisted photocatalysis, which is 16.6 and 2.44 times as that of piezocatalysis and photocatalysis, respectively. This performance is higher than most reported BaTiO3‐based piezo‐assisted photocatalysis systems. This work paves the way for the design of high‐efficiency piezo‐assisted photocatalytic materials for environmental remediation through using green energies in nature.

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.

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