Synergistic oxygen substitution and heterostructure construction in polymeric semiconductors for efficient water splitting

Abstract

<p>A synergistic oxygen substitution and heterostructure construction strategy was developed to synthesize oxygenated-triazine-heptazine-conjugated polymer nanoribbons for photocatalytic water splitting.</p>

Engineering Oxidation States of a Platinum Cocatalyst over Chemically Oxidized Graphitic Carbon Nitride Photocatalysts for Photocatalytic Hydrogen Evolution

“…In general, a smaller radius in the resulting Nyquist plot reflects a more effective separation of the photoinduced electrons and holes. ,,− As depicted in Figure D, the arc radii of Pt/AO and Pt/NO were significantly smaller than those of Pt/AB and Pt/NB, indicating that the chemically oxidized Pt/g-C 3 N 4 samples possessed higher charge transfer efficiency. This improvement can be attributed to (i) the aforementioned introduction of O-containing functional groups (COOH and OH), which have been shown to store negative charges and increase the space charge region thickness, thus leading to improvements in upward band bending and obviously enhanced charge separation ,− and (ii) the presence of the large work function Pt 2+ as an electron-deficient species in Pt/AO and Pt/NO, which can easily trap the photoexcited electrons from g-C 3 N 4 through the metal–semiconductor interface. , On the basis of the aforementioned discussion, we can confirm that the chemical oxidation process helps to accelerate the charge separation of photoinduced electrons and holes while inhibiting the recombination rate of these charge carriers, all of which benefit the formation of oxidized Pt 2+ phase, expediting the photocatalytic H 2 production.…”

Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

“…A comparison of the Pt/CN-160 EIS spectrum with those of its counterparts demonstrates that the former exhibits a smaller arc radius on the Nyquist plots, indicating its lower charge transfer resistance and the most effective photoinduced electron-hole pairs separation. This possibly results from the addition of O-containing functional groups that can act as electron acceptors and increase the thickness of the depletion region, hence improving the charge separation efficiency [49][50][51]. Another possible reason for this enhancement is the high work function of Pt 2+ , which has been in favor of the electron-withdrawing process, accelerating the electron transfer ability and enhancing the hydrogen evolution performance [46,48,52].…”

Progress and challenges in photocatalytic ammonia synthesis

“…Because of its excellent optical properties, low cost, and good stability, graphitic carbon nitride (g-C3N4) has attracted much scientific interest in the field of photocatalysis. [42][43][44][45][46][47][48][49][50][51][52][53] Dong et al have reported the application of the NVs-incorporated g-C3N4 (V-g-C3N4) for photoreduce N2. 54 They found that the N2 adsorption amount of V-g-C3N4 was 75.1 cm 3 g -1 , 2.4 times higher than that of g-C3N4 without NVs (30.9 cm 3 g -1 ), which suggested that the NVs on the surface of V-g-C3N4 could provide a number of chemisorption and activation sites for N2 molecules, leading to an NH3 production rate of 1.24 mmol h -1 gcat -1 under visible light irradiation in the presence of methanol as a hole scavenger.…”