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A one-step sol-gel method for SrSnO 3 nanoparticle synthesis and the incorporation of multi-walled carbon nanotubes (MWCNTs) to produce a SrSnO 3 @MWCNT photocatalyst is presented. The incorporation of MWCNTs results in enhancement of structural, optical, and optoelectrical properties of SrSnO 3 . The optimized 3.0% addition of MWCNTs results in light absorption enhancement and a reduction of the band gap from 3.68 to 2.85 eV. Upon application of the photocatalyst in the photocatalytic hydrogen production reaction, SrSnO 3 @MWCNT-3.0% yields 4200 μmol g -1 of H 2 in just 9 h with the use of 1.6 g L -1 of the photocatalyst. SrSnO 3 @MWCNT exhibits remarkable chemical and photocatalytic stability upon regeneration. Enhanced photocatalytic ability is attributed to improved surface properties and charge-carrier recombination suppression induced by the MWCNT addition. This study highlights the remarkable improvements in chemical and physical properties of semiconductors with MWCNT incorporation., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

The production of hydrogen using a new type of heterogeneous photocatalyst under visible light is considered a remarkable essential pathway for sustainable, pure energy not only on the laboratory scale but also on a bigger scale. Hence, a new nanocomposite of mesoporous MnCo 2 O 4 , g-C 3 N 4 , and MnCo 2 O 4 @g-C 3 N 4 was produced utilizing a sol-gel method with variable MnCo 2 O 4 contents. The crystal structure of MnCo 2 O 4 was effectively confirmed by the X-ray diffraction pattern and integrated onto the g-C 3 N 4 structure. The MnCo 2 O 4 nanoparticles were displayed as spherical particles by TEM images and dispersed in a uniform way inside the g-C 3 N 4 nanosheet. The synthesized nanocomposites in the form of MnCo 2 O 4 @g-C 3 N 4 were examined as a new effective photocatalyst against glycerol as a source for H 2 production with visible light. The MnCo 2 O 4 contents indicated a corroborative impact for the photocatalytic action related to the H 2 production process. A maximum H 2 production molecular value was observed (21,870 μmol·g -1 ·h -1 ) for a 1.5 wt % MnCo 2 O 4 @g-C 3 N 4 nanocomposite as a considerable increase in its photocatalytic activity. The yields of H 2 are ∼55 and 23 times higher than those of g-C 3 N 4 and MnCo 2 O 4 , respectively. Up to five times cycles of visible lighting were the maximum number of repeated cycles by which the 1.5 wt % MnCo 2 O 4 @g-C 3 N 4 product showed higher stability and durability., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

In this research, nanocomposites made of CuCr 2 O 4 -g-C 3 N 4 accommodating distinct contents of CuCr 2 O 4 (1-4 wt %) nanoparticles (NPs) were endorsed for hydrogen gas production after illumination by visible light in the presence of aqueous glycerol solution. The ultrasonication-mixture method was applied to assure the homogeneous distribution of CuCr 2 O 4 NPs over synthesized mesoporous g-C 3 N 4 . Such nanocomposites possess suppressed recombination between the photoinduced charges. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy examinations affirmed the formation of CuCr 2 O 4 -g-C 3 N 4 heterojunctions. The separation between the induced charges and the photocatalytic performance with the CuCr 2 O 4 NP amount were investigated. The CuCr 2 O 4 -g-C 3 N 4 heterojunction of 3 wt % CuCr 2 O 4 content was documented as the optimal heterojunction. Upgraded hydrogen gas generation was attained over the optimal heterojunction with the extent of ten and thirty times as those registered for pure CuCr 2 O 4 and g-C 3 N 4 specimens, respectively, under illumination by visible light. The photocatalytic performance acquired by the diverse synthesized specimens was assessed not only by their effectiveness to absorb light in the visible region but also by their potential to separate the photoinduced charges., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Fabrication of 3D mesoporous Ag 2 O-ZnO heterojunctions at varying Ag 2 O contents has been achieved through poly(ethylene glycol)- block -poly(propylene glycol)- block -poly(ethylene glycol) (Pluronic F-108) as the structure-directing agent for the first time. The mesoporous Ag 2 O-ZnO nanocomposites exhibited a mesoporous structure, which revealed a large pore volume and high surface area. The photocatalytic efficiency over mesoporous Ag 2 O-ZnO nanocomposites for tetracycline (TC) compared with that over commercial P-25 and pristine ZnO NPs through the visible light exposure was studied. Mesoporous 1.5% Ag 2 O-ZnO nanocomposites indicated the highest degradation efficiency of 100% of TC during 120 min of the visible light exposure compared with 5% and 10% for pristine ZnO NPs and commercial P-25, respectively. The TC degradation rate took place much rapidly over 1.5% Ag 2 O-ZnO nanocomposites (0.798 μmol L -1 min -1 ) as compared to either commercial P-25 (0.097 μmol L -1 min -1 ) or ZnO NPs (0.035 μmol L -1 min -1 ). The mesoporous 1.5% Ag 2 O-ZnO nanocomposite revealed the highest degradation rate among all synthesized samples, and it was 23 and 8 orders of magnitudes greater than those of pristine ZnO NPs and P-25, respectively. The photoluminescence and transient photocurrent intensity behaviors have been discussed to explore photocatalysis mechanisms. It is anticipated that the present work will contribute some suggestions for understanding other heterojunctions with outstanding behaviors., Competing Interests: The authors declare no competing financial interest., (© 2020 American Chemical Society.)