Capturing Visible Light in Low‐Band‐Gap C₄N‐Derived Responsive Bifunctional Air Electrodes for Solar Energy Conversion and Storage

Abstract

We report facile synthesis of low-band-gap mesoporous C 4 Np articles and their use as responsive bifunctional oxygen catalysts for visible-light-sensitive (VLS) rechargeable Zn-air battery (RZAB) and polymer-air battery (RPAB). Compared to widely studied g-C 3 N 4 ,C 4 Nshows asmaller band gap of 1.99 eV,with alarger photocurrent response,and it can function as visible-light-harvesting antenna and bifunctional oxygen reduction/evolution (ORR/OER) catalysts,e nabling effective photocoupling to tune oxygen catalysis.T he C 4 Nenabled VLS-RZAB displays al ow charge voltage of 1.35 V under visible light, which is belowt he theoretical RZAB voltage of 1.65 V, corresponding to ahigh energy efficiency of 97.78 %. Pairing aC 4 Nc athode with ap olymer anode also endows an VLS-RPAB with light-boosted charge performance. It is revealed that the ORR and OER active sites in C 4 Na re separate carbon sites near pyrazine-nitrogen atoms and photogenerated energetic holes can activate OER for improved reaction kinetics.

Photo-enhanced rechargeable high-energy-density metal batteries for solar energy conversion and storage

“…Since the OER process in ZAB is much similar to the PEC water-oxidation field, the sun-light-promoted ZAB using BiVO4 or α-Fe2O3 has also been proposed, where the BiVO4 cathode possesses a low charge potential of 1.2 V and that of α-Fe2O3 is ~ 1.43 V [94]. Recently, a low-band-gap mesoporous carbon nitride (C4N) has also been reported by Yu et al and can promote the OER process in ZAB [95]. Compared with g-C3N4, the narrow band gap of C4N, 1.99 eV, ensures sufficient absorption of visible light and promotes charge separation (Fig.…”

Vacuum-Dried and Intrinsic Photothermal Phenolic Carbon Aerogel from Coal Tar Rich in Polycyclic Aromatics for Efficient Solar Steam Generation

“…To understand the light absorption of CPCAs, models with variable aromatic rings were constructed (Figure S9) and their band gaps were calculated by MedeA 3.3.1 (Figure a). Obviously, band gaps vary greatly from 3.28 (all benzene rings) to 1.62 eV (with two anthracene rings substituting two benzene rings), indicating the great enhancement of light absorption. , Due to the existence of considerable polycyclic aromatics in coal tar, high light absorption can be achieved. Therefore, coal tar has a natural advantage for preparing photothermal materials.…”

Enhanced Photocatalytic Production of H2O2 through Regulation of Spatial Charge Transfer and Light Absorption over a MnIn2S4/WO3 (Yb, Tm) Z-Scheme System

“…The valance band spectra of WO 3 (10Yb, 5Tm) and MnIn 2 S 4 (Figure c,d) were measured, and their VB potentials were calculated to be 3.02 and 0.85 eV, respectively. Then their conduction band (CB) potentials were calculated to be 0.42 and −1.03 eV vs NHE according to eq . , Accordingly, it can be expected that a Z-scheme heterojunction is constructed by the combination of WO 3 (10Yb, 5Tm) and MnIn 2 S 4 , as shown in Scheme . The narrow difference in the energy level potential between the CB of WO 3 (10Yb, 5Tm) and the VB of MnIn 2 S 4 is beneficial for the carrier separation in the Z-scheme system. − As a result, the photogenerated electrons accumulated on the CB of MnIn 2 S 4 have a high reduction ability for H 2 O 2 formation, due to their more negative potential than that for O 2 activation (O 2 → H 2 O 2 (2e – process), 0.695 eV vs NHE; O 2 → • O 2 – (1e – process), −0.33 eV vs NHE).…”

“…Then their conduction band (CB) potentials were calculated to be 0.42 and −1.03 eV vs NHE according to eq 6. 79,80 Accordingly, it can be expected that a Z-scheme heterojunction is constructed by the combination of WO 3 (10Yb, 5Tm) and MnIn 2 S 4 , as shown in Scheme 1. The narrow difference in the energy level potential between the CB of WO 3 (10Yb, 5Tm) and the VB of MnIn 2 S 4 is beneficial for the carrier separation in the Z-scheme system.…”