Green Light Photoelectrocatalysis with Sulfur‐Doped Carbon Nitride: Using Triazole‐Purpald for Enhanced Benzylamine Oxidation and Oxygen Evolution Reactions

Abstract

Materials dictate carbon neutral industrial chemical processes. Visible‐light photoelectrocatalysts from abundant resources will play a key role in exploiting solar irradiation. Anionic doping via pre‐organization of precursors and further co‐polymerization creates tuneable semiconductors. Triazole derivative‐purpald, an unexplored precursor with sulfur (S) container, combined in different initial ratios with melamine during one solid‐state polycondensation with two thermal steps yields hybrid S‐doped carbon nitrides (C3N4). The series of S‐doped/C3N4‐based materials show enhanced optical, electronic, structural, textural, and morphological properties and exhibit higher performance in organic benzylamine photooxidation, oxygen evolution, and similar energy storage (capacitor brief investigation). 50M‐50P exhibits the highest photooxidation conversion (84 ± 3%) of benzylamine to imine at 535 nm – green light for 48 h, due to a discrete shoulder (≈700) nm, high sulfur content, preservation of crystal size, new intraband energy states, structural defects by layer distortion, and 10–16 nm pores with arbitrary depth. This work innovates by studying the concomitant relationships between: 1) the precursor decomposition while C3N4 is formed, 2) the insertion of S impurities, 3) the S‐doped C3N4 property‐activity relationships, and 4) combinatorial surface, bulk, structural, optical, and electronic characterization analysis. This work contributes to the development of disordered long‐visible‐light photocatalysts for solar energy conversion and storage.

Multifunctional carbon nitride nanoarchitectures for catalysis

“…Benefiting from their similar radial size and electronegativity of C and N atoms, it is quite straightforward to substitute the light elements B, S and P atoms in the lattice of the CN framework as nonmetal doping plays an important role in controlling the electronic structure, reducing the band gap, enhancing the visible light absorption, suppressing the recombination of charge carriers and creating more active sites. [188][189][190] Along with an exploration of boron nitride, B-doped g-CN (BCN) has received lots of attention in order to reduce and modulate the band structure of the boron nitride that possesses a wide band gap of 45.7 eV. 191 The band structure could be finely regulated depending on the composition of the trio of elements.…”

Carbon Nitride-Based Nanomaterials as a Sustainable Catalyst for Biodiesel Production

“…In addition, for mpg-C 3 N 4 , symmetrical pores were recognized in its flake structure. A variety of CN-based nanomaterials have been previously studied in the literature, and all of them presented layer/flake morphology with unique characteristics. − …”

A Guide to Chemical Reactions Design in Carbon Nitride Photocatalysis

“…The community of materials scientists is focused on optimizing structure of g‐CNs to improve efficiency of photon absorption – to shift the onset of absorption more into the visible range of the electromagnetic spectrum, i. e. narrow the band gap, exciton separation, carrier diffusion and carrier transport (gears one‐to‐four). Typically, this is achieved by doping of g‐CN structure with heteroelements, [96,97] introducing a defined number of defects, such as carbon vacancies, [98,99] creating heterojunction composites with other semiconductors, [100] and adding co‐catalysts [101,102] . These strategies have been reviewed [103,20,104,105] .…”