Electron-Deficient Zn-N6 Configuration Enabling Polymeric Carbon Nitride for Visible-Light Photocatalytic Overall Water Splitting

Abstract

Despite of suitable band structures for harvesting solar light and driving water redox reactions, polymeric carbon nitride (PCN) has suffered from poor charge transfer ability and sluggish surface reaction kinetics, which limit its photocatalytic activity for water splitting. Herein, atomically dispersed Zn-coordinated three-dimensional (3D) sponge-like PCN (Zn-PCN) is synthesized through a novel intermediate coordination strategy. Advanced characterizations and theoretical calculations well evidence that Zn single atoms are coordinated and stabilized on PCN in the form of Zn-N6 configuration featured with an electron-deficient state. Such an electronic configuration has been demonstrated contributive to promoted electron excitation, accelerated charge separation and transfer as well as reduced water redox barriers. Further benefited from the abundant surface active sites derived from the 3D porous structure, Zn-PCN realizes visible-light photocatalysis for overall water splitting with H2 and O2 simultaneously evolved at a stoichiometric ratio of 2:1. This work brings new insights into the design of novel single-atom photocatalysts by deepening the understanding of electronic configurations and reactive sites favorable to excellent photocatalysis for water splitting and related solar energy conversion reactions. "Image missing"

Electron-rich pyrimidine rings enabling crystalline carbon nitride for high-efficiency photocatalytic hydrogen evolution coupled with benzyl alcohol selective oxidation

“…40 Furthermore, this charge density redistribution would enable the separation of redox reactive sites, promoting charge carrier separation and suppressing back reactions, which is believed to benefit the photocatalytic activity. 41 Above theoretical calculation results suggest that the introduced electron-rich pyrimidine rings could promote exciton dissociation and charge separation by inducing the charge density redistribution in CCN-Pr x . To strengthen this deduction, XANES spectra were further recorded in dark and under illumination at C K-edge and N K-edge to monitor the photoexcited electronic transitions (Fig.…”

Single‐atom catalyst application in distributed renewable energy conversion and storage

“…Similar to homogeneous catalysis, SACs present a well‐defined atomic structure and an adjustable coordination environment 1,2 . In recent years, SACs have become one of the best candidates for distributed energy (such as solar energy, wind energy, and tidal energy) conversion and storage due to the sufficient active sites and ultrahigh reaction selectivity 3–8 …”

“…Therefore, how to prepare SACs with stable structures in high metal loading is still a huge challenge 9,10 . Moreover, in consideration of the industrial applications, it is necessary for SACs to be prepared on a large scale 6 . In this review, some recently reported literatures are introduced for obtaining SACs in high metal loading or on a large scale.…”

“…SACs uniformly distribute metals on the support to form monodispersed energy, wind energy, and tidal energy) conversion and storage due to the sufficient active sites and ultrahigh reaction selectivity. [3][4][5][6][7][8] However, when the size of metal particles decreases to an SA level, the metal surface free energy is increased dramatically. So, neighboring SAs have the tendency to aggregate into clusters or nanoparticles.…”

The 2D van der Waals heterojunction MoC@NG@CN for enhanced photocatalytic hydrogen production

“…4,5 The photocatalytic water splitting reaction needs to meet both thermodynamic and kinetic requirements. 6 Photocatalytic hydrogen production is an uphill reaction in terms of thermodynamics, requiring 237.2 kJ energy per mole of water to decompose under standard conditions. 7,8 With respect to kinetics, the conduction band of photocatalysts demands an electrochemical potential spanning the water reduction potential.…”