Ultrafine Cobalt Catalysts on Covalent Carbon Nitride Frameworks for Oxygenic Photosynthesis

Abstract

The rational cooperation of sustainable catalysts with suitable light-harvesting semiconductors to fabricate photosynthetic device/machinery has been regarded as an ideal technique to alleviate the current worldwide energy and environmental issues. Cobalt based species (e.g., Co-Pi, Co3O4, and Co-cubene) have attracted particular attentions because they are earth-abundant, cost-acceptable, and more importantly, it shows comparable water oxidation activities to the noble metal based catalysts (e.g., RuO2, IrO2). In this contribution, we compared two general cocatalysts modification strategies, based on the surface depositing and bulk doping of ultrafine cobalt species into the sustainable graphitic carbon nitride (g-C3N4) polymer networks for oxygenic photosynthesis by splitting water into oxygen, electrons, and protons. The chemical backbone of g-C3N4 does not alter after both engineering modifications; however, in comparison with the bulk doping, the optical and electronic properties of the surface depositing samples are efficiently promoted, and the photocatalytic water oxidation activities are increased owing to much more exposed active sites, reduced overpotential for oxygen evolution and the accelerated interface charge mobility. This paper underlines the advantage of surface engineering to establish efficient advanced polymeric composites for water oxidation, and it opens new insights into the architectural design of binary hybrid photocatalysts with high reactivity and further utilizations in the fields of energy and environment.

A Cobalt‐Modified Covalent Triazine‐Based Framework as an Efficient Cocatalyst for Visible‐Light‐Driven Photocatalytic CO2 Reduction

“…The optical properties of CTF‐1 and Co/CTF‐1 were studied by UV‐vis absorption spectroscopy (Figure a). Obviously, Co/CTF‐1 series samples exhibited an enhanced optical absorption for the visible light (450–700 nm) compared with that of CTF‐1, indicating the great host‐guest interaction between metal and frameworks . The charge carrier behaviors of the samples were investigated by photoluminescence (PL) with excitation wavelength of 420 nm (Figure b).…”

Strategies for Efficient Solar Water Splitting Using Carbon Nitride

“…Similarly, Co 3 O 4 /g‐C 3 N 4 hybrid photocatalyst achieved an AQE of 1.1 % at 420 nm for water oxidation . In addition, ultrafine cobalt species, and NiFe/N‐doped graphene are also efficient OECs for g‐C 3 N 4 .…”

Artificial Photosynthesis with Polymeric Carbon Nitride: When Meeting Metal Nanoparticles, Single Atoms, and Molecular Complexes

“…It has been well documented that the four‐electron O 2 evolution reaction requires more energy to break the OH bond and build the OO bond, while the two‐electron process for H 2 O 2 formation could always reach a higher reaction rate, resulting in the preferable generation of H 2 O 2 during the actual water splitting reaction . To accelerate the kinetics of the half water oxidation reaction, Co(OH), CoSe 2 , CoO x , Ni–Co Layered double hydroxides, and cobalt ions were adopted to serve as water oxidation cocatalysts to promote the O 2 production activity of PCN. For the improved overall water splitting activity, various strategies have been developed to modify the PCN based photocatalysts by integrating with metal nanoparticles, metal single atoms, and metal molecular complexes.…”