Enhancing Electron Transfer and Electrocatalytic Activity on Crystalline Carbon-Conjugated g-C₃N₄

Abstract

Carbon nitride (g-C 3 N 4 ) materials are electroactivated for oxygen reduction (ORR) and oxygen evolution (OER) reactions when they are supported by conductive carbons. However, the electrocatalytic process on semiconductor-based heterostructures such as carbon-supported g-C 3 N 4 still suffers from a huge energy loss because of poor electron mobility. Here, we demonstrated a concept that the conjugation of g-C 3 N 4 with crystalline carbon can improve the in-plane electron mobility and make interior triazine units more electro-active for ORR and OER. As a result, the Co metal coordinated g-C 3 N 4 with crystalline carbons (Co− C 3 N 4 /C) showed a remarkable electrocatalytic performance toward both ORR and OER. For example, it displayed an onset potential of 0.95 V for ORR and an overpotential of 1.65 V for OER at 10 mA cm −2 , which are comparable and even better than those of benchmark Pt, RuO 2 , and other carbon nitride-based electrocatalysts. As a proof-of-concept application, we employed this catalyst as an air electrode in the rechargeable aluminum-air battery, which showed more rechargeable and practicable than those of Pt/C and RuO 2 catalysts in two-electrode coin battery. The characterization results identified that the good performance of Co−C 3 N 4 /C was primarily attributed to the enhanced in-plane electron mobility by crystalline carbon conjugation and the Co-coordinated g-C 3 N 4 along with nitrogen-doped carbons.

Modulating the Electronic Structure of Single‐Atom Catalysts on 2D Nanomaterials for Enhanced Electrocatalytic Performance

“…Niu et al provided another approach to enhance the electron transfer and electrocatalytic activity through the in situ introduction of crystalline carbon structure within g‐C 3 N 4 skeleton (Figure b). In this work, the precursor mixture of melamine, lactose, Co(NO 3 ) 2 , and NaCl underwent the first‐step polymerization below 500 °C and then converted into Co coordinated g‐C 3 N 4 that comprised of crystalline carbons under 700 °C …”

Thermodynamically Stable Mesoporous C3N7 and C3N6 with Ordered Structure and Their Excellent Performance for Oxygen Reduction Reaction

“…The strategy of compositing the g‐C 3 N 4 with carbon materials brought a huge improvement in ORR activity of the g‐C 3 N 4. However the catalytic activities of g‐C 3 N 4 /carbon composites still need to be improved in order to be comparable to metal‐based electrocatalysts. It is important to engineer a core structure of carbon nitride to increase the activity of carbon nitride itself, then activity of its composites could be further improved.…”

Improved Photoactivities of Large‐surface‐area g‐C3N4 for CO2 Conversion by Controllably Introducing Co‐ and Ni‐Species to Effectively Modulate Photogenerated Charges

“…Surface composition and valence state of elements in the catalysts were analyzed with XPS. The peaks position at 779.2 eV and 795.2 eV in the XPS result for Co2p (Figure A) are attributed to the Co2p 3/2 and Co2p 1/2 of Co(II) . The two peaks centered at 856.5 eV and 871.8 eV in the XPS result for Ni2p (Figure B) are attributed to the Ni 2p 3/2 and Ni 2p 1/2 of Ni(II) .…”