Mn_0.4In_1.6S₃ Nanoflower Solid Solutions for Visible-Light Photocatalytic Hydrogen Evolution

Abstract

A series of Mn2x In2(1–x)S3 (x < 0.5) nanoflower solid solutions (NSS) were synthesized by a simple one-step hydrothermal method using l-cysteine as S source and chelating reagent. The Mn2x In2(1–x)S3 NSS exhibit excellent hydrogen evolution performance compared with pure In2S3. In particular, the Mn0.4In1.6S3 nanoflower solid solution exhibits the best photocatalytic activity with a hydrogen evolution rate of up to 3570 μmol/(g h) under visible-light irradiation even without any noble metal or cocatalysts, which is about 22 times as high as the pure In2S3 dose, and it shows a favorable stability in catalytic and antiphotocorrosion properties. The apparent quantum efficiency of Mn0.4In1.6S3 NSS was 12.9% at 420 nm. The excellent photoactivity of Mn0. 4In1.6S3 NSS is mainly related to faster separation of photogenerated electron–hole pairs and the band-gap structures. Additionally, the Mn0.4In1.6S3 NSS possesses another active site of Mn for hydrogen evolution compared with pure In2S3, and density functional theory (DFT) simulations for the H binding free energy on active site (ΔG H* ) are performed to gain the fundamental insight into the role of Mn in Mn0. 4In1.6S3 NSS. Furthermore, because of the Mn active site, the Mn0.4In1.6S3 NSS has a very appealing ΔG H* of 0.74 eV, which is closer to zero than In as active sites in both Mn0.4In1.6S3 NSS (−3.83 eV) and pure In2S3 (−4.29 eV). The DFT-based first-principles calculations clearly shows that hydrogen adsorbed at different reaction sites with Mn and In have distinctly different free energies which further impact on hydrogen evolution performance. The research lights a new insight for photocatalytic hydrogen evolution, thus broadening routes for designing photocatalytic materials with multiple reaction sites for enhanced photocatalysis.

Construction of Porous Tubular In2S3@In2O3 with Plasma Treatment-Derived Oxygen Vacancies for Efficient Photocatalytic H2O2 Production in Pure Water Via Two-Electron Reduction

“…As can be seen more clearly in Figure e, the In 2 S 3 grown on the O v /In 2 O 3 can exhibit a flowerlike structure with a size of about 200 nm in diameter, which might serve as the outer photosenitizer for the visible-light absorption, whereas the inner O v /In 2 O 3 might provide a plenty of photoelectrons for the ORR toward the H 2 O 2 evolution. Moreover, Figure f displays the high-resolution transmission electron microscopy (TEM) image, showing the crystal lattice spacings of 0.27 and 0.29 nm, which can well match to the (400) facet of cubic In 2 S 3 and (222) facet of cubic In 2 O 3 , respectively. , The morphological characteristic results above manifest that the In 2 S 3 @O v /In 2 O 3 composites should be successfully fabricated. In addition, the elemental mapping by energy-disperse spectroscopy was employed to investigate the element distributions of In 2 S 3 @O v /In 2 O 3 , proving that the elements In, O, and S are uniformly distributed in the composites (Figure S5).…”

Solar Fuel Production from Hydrogen Sulfide: An Upstream Energy Perspective

“…It also improves solar energy utilization by narrowing the bandgap of the solid-solution Mn 2x In 2(1Àx) S 3 from 1.82 to 1.58 eV. [41] At the same time, Cu doping broadens the spectral response of a catalyst and allows Reproduced with permission. [37] Copyright 2017, Wiley VCH.…”

“…For example, DFT calculations demonstrated that Δ G H * of In 2 S 3 doped with Mn is 0.74 eV, while Δ G H* of pure In 2 S 3 is −4.29 eV. [ 41 ] Likewise, DFT calculations of the sulfur adsorption energy ( E ads ) revealed that sulfur desorption from Cu‐doped β ‐In 2 S 3 ((In x Cu 1− x ) 2 S 3 ) is more favorable (−0.37 eV) than from an individual β ‐In 2 S 3 (−2.01 eV). [ 42 ] Hence, Mn doping increases the HER rate by rapid adsorption/desorption of H intermediates.…”

Manganese Cadmium Sulfide Nanoparticles Solid Solution on Cobalt Acid Nickel Nanoflakes: A Robust Photocatalyst for Hydrogen Evolution

“…The ionic radius of Zn 2+ , Mn 2+ and Cd 2+ are 0.074 nm, 0.064 nm and 0.092 nm. From this, the Mn 2+ possesses a smaller ionic radius, facilitating to form the Mn x Cd 1‐ x S solid solution easily [10] . Therefore, exploring the Mn x Cd 1‐ x S solid solution has become more and more attractive to satisfy the practical application.…”

“…From this, the Mn 2 + possesses a smaller ionic radius, facilitating to form the Mn x Cd 1-x S solid solution easily. [10] Therefore, exploring the Mn x Cd 1-x S solid solution has become more and more attractive to satisfy the practical application. The photocatalytic H 2 production performance of the pure Mn x Cd 1-x S solid solution is enhanced compared to pure CdS, but there still exists a lot of room for improvement.…”