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Rawool SA, Pai MR, Banerjee AM, Nath S, Bapat RD, Sharma RK, Jagannath, Dutta B, Hassan PA, Tripathi AK. Superior Interfacial Contact Yields Efficient Electron Transfer Rate and Enhanced Solar Photocatalytic Hydrogen Generation in M/C 3N 4 Schottky Junctions. ACS Appl Mater Interfaces 2023; 15:39926-39945. [PMID: 37556210 DOI: 10.1021/acsami.3c05833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Various literature studies (Table 6) have reported that dispersion of metal nanoparticles (NPs) on graphitic carbon nitride g-C3N4 (M/CN) has considerably improved the photocatalytic hydrogen yield. It is understood that metal NPs create active sites on the surface of CN and act as a cocatalyst. However, the precise changes induced by different metal NPs on the surface of CN still elude us. Here, we report a thorough understanding and comparison of the morphology, metal-support interactions, interfacial charge transfer kinetics, and band characteristics in different M/CN (M = Pt, Pd, Au, Ag, Cu) correlated with photocatalytic activity. Among all metals, Pt/CN was found to be the best performer both under sunlight and UV-visible irradiation. Under sunlight, maximum H2@ 2.7 mmol/h/g was observed over Pt/CN followed by Pd/CN > Au/CN > Ag/CN > Cu/CN ≈ CN. The present study revealed that among all metals, Pt formed superior interfacial contact with g-C3N4 as compared to other metals. The maximum Schottky barrier height (Φb,Pt) of 0.66 V was observed at Pt/CN followed by Φb,Au/CN (0.46 V) and Φb,Pd/CN (0.05 V). The presence of electron-deficient Pt in Pt-XPS, decrease in the intensity of d-DOS of Pt near the Fermi level in VB-XPS, increase in CB tail states, and cathodic shift in Vfb in MS plots sufficiently confirmed strong metal-support interactions in Pt/CN. Due to the SPR effect, Au and Ag NPs suffered from agglomeration and poor dispersion during photodeposition. Finely dispersed Pt NPs (2-4 nm, 53% dispersion) successfully competed with shallow/deep trap states and drove the photogenerated electrons to active metallic sites in a drastically reduced time period as investigated by femtosecond transient absorption spectroscopy. Typically, an interfacial electron transfer rate, KIET,avg, of 2.5 × 1010 s-1 was observed for Pt/CN, while 0.087 × 1010 s-1 was observed in Au/CN. Band alignment/potentials at M/CN Schottky junctions were derived and most favorable in Pt/CN with CB tail states much above the water reduction potential; however, in the case of Pd, these extend much below the H+/H2 potential and hence behave like deep trap states. Thus, in Pd/CN (τ0 = 4200 ps, 49%) and Ag/CN (3870 ps, 53%), electron deep trapping dominates over charge transfer to active sites. The present study will help in designing futuristic new cocatalyst-photocatalyst systems.
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Affiliation(s)
- Sushma A Rawool
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
| | - Mrinal R Pai
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
| | - A M Banerjee
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
| | - S Nath
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
| | - R D Bapat
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, Maharashtra India
| | - R K Sharma
- Technical Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India
| | - Jagannath
- Technical Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra, India
| | - B Dutta
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
| | - P A Hassan
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
| | - A K Tripathi
- Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, Maharashtra India
- Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra India
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Banerjee AM, Pai MR, Arya A, Bharadwaj SR. Photocatalytic H2 generation over In2TiO5, Ni substituted In2TiO5 and NiTiO3 – a combined theoretical and experimental study. RSC Adv 2015. [DOI: 10.1039/c5ra10531e] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Role of Ni substitution in modifying the crystal structure, optical absorption properties and electronic properties of indium titanate, In2(1−x)Ni2xTiO5−δ (0.0 ≤ 2x ≤ 0.4) and its consequent effect on the photocatalytic properties for H2 generation.
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Affiliation(s)
- A. M. Banerjee
- 3-189 H Modular Labs
- Fuel Cell Materials and Catalysis Section
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai–400085
| | - M. R. Pai
- 3-189 H Modular Labs
- Fuel Cell Materials and Catalysis Section
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai–400085
| | - A. Arya
- Material Science Division
- Bhabha Atomic Research Centre
- Mumbai–400085
- India
| | - S. R. Bharadwaj
- 3-189 H Modular Labs
- Fuel Cell Materials and Catalysis Section
- Chemistry Division
- Bhabha Atomic Research Centre
- Mumbai–400085
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