11 Jul 11:57
by Jinfa Chang,
Guanzhi Wang,
Zhenzhong Yang,
Boyang Li,
Qi Wang,
Ruslan Kuliiev,
Nina Orlovskaya,
Meng Gu,
Yingge Du,
Guofeng Wang,
Yang Yang
An ultrahigh activity and selectivity seawater electrolyzer with robust stability is developed via a dual-doping and synergism optimization of Fe,P-NiSe2 nanoporous films. The Fe cation increases the selectivity and Faraday efficiency, while the P anion improves the electronic conductivity and prevents the dissolution of selenide.
Abstract
Hydrogen (H2) production from direct seawater electrolysis is an economically appealing yet fundamentally and technically challenging approach to harvest clean energy. The current seawater electrolysis technology is significantly hindered by the poor stability and low selectivity of the oxygen evolution reaction (OER) due to the competition with chlorine evolution reaction in practical application. Herein, iron and phosphor dual-doped nickel selenide nanoporous films (Fe,P-NiSe2 NFs) are rationally designed as bifunctional catalysts for high-efficiency direct seawater electrolysis. The doping of Fe cation increases the selectivity and Faraday efficiency (FE) of the OER. While the doping of P anions improves the electronic conductivity and prevents the dissolution of selenide by forming a passivation layer containing P–O species. The Fe-dopant is identified as the primary active site for the hydrogen evolution reaction, and meanwhile, stimulates the adjacent Ni atoms as active centers for the OER. The experimental analyses and theoretical calculations provide an insightful understanding of the roles of dual-dopants in boosting seawater electrolysis. As a result, a current density of 0.8 A cm−2 is archived at 1.8 V with high OER selectivity and long-term stability for over 200 h, which surpasses the benchmarking platinum-group-metals-free electrolyzers.
11 Jul 05:30
by Jun Yang,
Jianfang Jing,
Yongfa Zhu
A full-spectrum responsive donor–acceptor supramolecular photocatalyst TPPS/C60 is successfully constructed. The theoretical spectral efficiency of TPPS/C60 is as high as 70%. The TPPS/C60 performs with a highly efficient photocatalytic H2 evolution rate of 34.57 mmol g−1 h−1, surpassing many reported organic photocatalysts. The D–A structure and the giant internal electric field dramatically promote the charge separation.
Abstract
A full-spectrum (300–850 nm) responsive donor–acceptor (D–A) supramolecular photocatalyst tetraphenylporphinesulfonate/fullerene (TPPS/C60) is successfully constructed. The theoretical spectral efficiency of TPPS/C60 is as high as 70%, offering the possibility of full-solar-spectrum light harvesting. The TPPS/C60 performs a highly efficient photocatalytic H2 evolution rate of 276.55 µmol h−1 (34.57 mmol g−1 h−1), surpassing many reported organic photocatalysts. The D–A structure effectively promotes electron transfer from TPPS to C60, which is beneficial to the photocatalytic reaction. Specifically, a giant internal electric field in the D–A structure is built via the enhanced molecular dipole, which dramatically promotes the charge separation (CS) efficiency by 2.35 times. Transient absorption spectra results show a long-lived CS state TPPS•+–C60
•− in the D–A structure, which effectively promotes participation of photogenerated electrons in the reduction reaction. Briefly, this work provides a novel approach for designing high-performance photocatalytic materials via enhancing the interfacial electric field.