A well-designed honeycomb Co3O4@CdS photocatalyst derived from cobalt foam for high-efficiency visible-light H2 evolution. Issue 19 (4th May 2021)

• Record Type: Journal Article
• Authors: Zhang, Chao; Liu, Baoquan; Li, Weiping; Liu, Xiangxue; Wang, Ke; Deng, Yifeng; Guo, Zhenmei; Lv, Zhiguo
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 19(2021)
• Page Start: 11665
• Page End: 11673
• Publication Date: 2021-05-04
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta11433b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A well-designed honeycomb Co3 O4 @CdS photocatalyst derived from cobalt foam was synthesized for high-efficiency visible-light H2 evolution ( ca. 16 320 μmol h −1 g −1 ). Abstract : Well-designed honeycomb Co3 O4 @CdS (H-Co3 O4 @CdS) was fabricated via a one-step strategy for efficient water splitting. During the decoration of CdS, honeycomb Co3 O4 (H-Co3 O4 ) with macropores was formed simultaneously. H-Co3 O4 could enhance CdS visible-light absorption capacity conspicuously and narrow its band gap from 2.08 to 1.03 eV. Therefore, H-Co3 O4 @CdS presented a remarkable H2 production of up to ca. 16 320 μmol g −1 h −1 ( λ > 420 nm), nearly 7.3 times higher than that of pristine CdS, indicating the excellent synergistic effect between H-Co3 O4 and CdS. Through various photoelectricity tests ( e.g., PL spectra, EPR, photoelectric responsiveness and impedance), it could be found that the distinguished H2 evolution was attributed to the improved charge carrier separation and electron generation. What's more, the enhanced H2 production of H-Co3 O4 @CdS is related to the improved specific surface area (83.49 m 2 g −1 ) and pore volume (0.247 cm 3 g −1 ) as well. Density Functional Theory (DFT) calculations confirmed that CdS has the function of diverting electrons, and the orbital energy level of absorbed H2 O molecules showed obvious migration due to the accumulation of electrons. Besides, the d-band of Co could induce more electrons to traverse the Fermi level. Subsequently, more electrons could be transferred from Co3 O4 to CdS and break the O–H1 bond. Compared to the H-Co3 O4 @CdS system, the d-band center of the Co atoms in H-Co3 O4 @CdS–H2 O shifted from −5.83 to −2.58 eV, thereby demonstrating that Co3 O4 served as an electron reservoir for charge redistribution in the photocatalytic water splitting process. In the end, a practicable mechanism for H-Co3 O4 @CdS about H2 O dissociation and H2 desorption was proposed.