CoAl₂O₄–g-C₃N₄ Nanocomposite Photocatalysts for Powerful Visible-Light-Driven Hydrogen Production

Abstract

There is no doubt that the rate of hydrogen production via the water splitting reaction is profoundly affected to a remarkable degree based on the isolation of photogenerated electrons from holes. The precipitation of any cocatalysts on the substrate surfaces (including semiconductor materials) provides significant hindrance to such reincorporation. In this regard, a graphite-like structure in the form of mesoporous g-C 3 N 4 formed in the presence of a template of mesoporous silica has been synthesized via the known combustion method. Hence, the resulting g-C 3 N 4 nanosheets were decorated with varying amounts of mesoporous CoAl 2 O 4 nanoparticles (1.0–4.0%). The efficiencies of the photocatalytic H 2 production by CoAl 2 O 4 -doped g-C 3 N 4 nanocomposites were studied and compared with those of pure CoAl 2 O 4 and g-C 3 N 4 . Visible light irradiation was carried out in the presence of glycerol as a scavenger. The results showed that the noticeable photocatalytic enhancement rate was due to the presence of CoAl 2 O 4 nanoparticles distributed on the g-C 3 N 4 surface. The 3.0% CoAl 2 O 4 –g-C 3 N 4 nanocomposite had the optimum concentration. This photocatalyst showed extremely high photocatalytic activities that were up to 22 and 45 times greater than those of CoAl 2 O 4 and g-C 3 N 4 , respectively. This photocatalyst also showed 5 times higher photocatalytic stability than that of CoAl 2 O 4 or g-C 3 N 4 . The presence of CoAl 2 O 4 nanoparticles as a cocatalyst increased both the efficiency and productivity of the CoAl 2 O 4 –g-C 3 N 4 photocatalyst. This outcome was attributed to the mesostructures being efficient charge separation carriers with narrow band gaps and high surface areas, which were due to the presence of CoAl 2 O 4 .

Synthesis and E-metric Studies of an Economically Viable Heterogeneous Acid Catalyst for Production and Upscaling of Solketal

“…The obtained result indicates that after the dispersion of TiO 2 over CoAl 2 O 4 spinel, no changes were observed in the mesoporous nature of the modified catalyst. The specific surface area of SCAT (3:2), in which SC was modified with ST, was 6.7 m 2 /g; the decrease in the surface area could be attributed to the incorporation of ST in the lattice site of the SC surface. , …”

Structure and Electron Engineering for Nitrate Electrocatalysis to Ammonia: Identification and Modification of Active Sites in Spinel Oxides

“…The peak at 74.38 eV can be assigned to the Al 2p (Figure 4d). [ 32 ] O 1s XPS spectrum of Co 3 O 4 is shown in Figure S4 (Supporting Information). These peaks can be respectively ascribed to M─O, surface oxygen vacancy, and surface adsorption of oxygen.…”

Recent Breakthroughs and Future Potential of Inorganic Nanocomposites in Hydrogen Generation

“…The doping of cocatalyst (CoAl 2 O 4 ) imposed over nanosheets (g-C 3 N 4 ) escalates both productivity and evolution rate. [111] For the first time, investigators analyzed the CoÀ NÀ CX catalyst because metallic interaction suitably affects HER operations. Using past remarkable results, Zhang and coworkers supplemented Co NPs over nitrogen-riched carbon nanosheets, producing CoÀ NÀ C0.025 M [from 0.025 M Co(NO 3 ) 2 ].…”

“…It could be seen that 3 % of the cocatalyst (CoAl 2 O 4 ) was treated at maximum concentration. The doping of cocatalyst (CoAl 2 O 4 ) imposed over nanosheets (g‐C 3 N 4 ) escalates both productivity and evolution rate [111] …”

“…After that, supplementation of the early-formed, highly active Ag/C layer over Ni metal positively impacts the synthesis of metal-based silver catalysts. Upon close XRD evaluation, the miller indices (111) for the preferred catalyst and linear sweep voltammograms reveal a redox reaction where Ag + $ Ag(s) coupling occurs at the catalyst surface. Here, the experimental result uses an unexpected optimal concentration of KOH (6 M) to perform the proposed heterocatalysts.…”