Hai-Yang Yu

Bio: Hai-Yang Yu is an academic researcher from Sun Yat-sen University. The author has contributed to research in topics: Alcohol oxidation & Cerium(IV) sulfate. The author has an hindex of 2, co-authored 4 publications receiving 13 citations.

Enhancement of the visible-light absorption and charge mobility in a zinc porphyrin polymer/g-C3N4 heterojunction for promoting the oxidative coupling of amines

Abstract: Graphitic carbon nitride (g ­ C3N4, CN) has been widely used as a photocatalyst due to its high stability and suitable band gap. However, its further development is limited due to inefficient light harvesting and rapid recombination of photogenerated carriers. In this study, a visible-light-responsive zinc porphyrin (ZnP)/CN heterojunction photocatalyst was synthesized by the combination of CN and a zinc-porphyrin-conjugated microporous polymer (ZnP-CMP). ZnP/CN exhibited excellent photocatalytic activity for the oxidative coupling of amines to imines under visible-light irradiation. The efficiency of the as-developed photocatalyst was 25 times greater than that of CN and about 2 times greater than that of ZnP-CMP. The significantly enhanced catalytic efficiency was attributed to the promotion of visible-light harvesting and photogenerated charge mobility via the introduction of ZnP-CMP. The ZnP/CN heterojunction photocatalyst also exhibited excellent broad substrate scope, stability, and reusability.

Cerium(IV) Sulfate as a Cocatalyst for Promoting the Direct Epoxidation of Propylene by Ruthenium Porphyrin with Molecular Oxygen

Abstract: The direct epoxidation of propylene to propylene oxide (PO) using molecular oxygen is difficult to achieve. Liquid-phase aerobic propylene epoxidation has been achieved using metalloporphyrin catal...

Oxygen vacancy enhanced visible light photocatalytic selective oxidation of benzylamine over ultrathin Pd/BiOCl nanosheets

Abstract: Two atomic layered BiOCl nanosheets with rich oxygen vacancies (NS-OV) were constructed via surface Pd deposition (0.5 wt%) as a multifunctional photocatalyst (Pd 0.5 /NS-OV), which exhibits high conversion (>95%) and precise selectivity (>98%) for benzylamine coupling to N-benzylidenebenzylamine under visible light irradiation and 1 atm air pressure. XPS and UV–vis DRS indicated that ultrathin structure of the nanosheets induces the formation of surface oxygen vacancies (OV), resulting in abundant surface low-coordinated Bi atoms and expanded visible light absorpion. Moreover, in-situ EPR results revealed that surface OV sites contribute to assemble O 2 molecules from air to surface of NS-OV. Additionally, in-situ FTIR suggested that low-coordinated Bi selectively adsorb benzylamine molecules via -N···Bi- coordination bonds at the interfaces, inducing polarization and activation of -C-N bonds. Furthermore, Pd sites were observed to crucially participate in formation of active ∙O 2 - species under visible light irradiation. Based on multifunctional features, a possible synergistic mechanism was proposed. The ultrathin structure of the NS-OV result in the generation of oxygen vacancies (OV) on the surfaces, leading to an abundant low-coordinated Bi atoms on the surfaces of the NS-OV and an expansion of light absorpion to visible light. Surface OV sites play an important role in assembling O 2 molecules from air to the surface of NS-OV. Moreover, the low-coordinated Bi sites on the surfaces lead to the selective adsorption of benzylamine molecules via the formation of the -N···Bi- coordination bonds at the interfaces, which induces the polarization and activation of -C-N bonds. Furthermore, the Pd nanoparticles on the surfaces were observed to crucially participate in the formation of the active ∙O 2 - anion radicals under visible light irradiation of the catalyst. Based on these multifunctional features, the precise synthesis of N-benzylidenebenzylamine from coupling of benzyamine is available under visible light irradiation and 1 atm air pressure at room temperature. • Two atomic BiOCl nanosheets with rich oxygen vacancies was designed as a multifunctional catalyst via Pd deposition. • Surface oxygen vacancies are the main sites to assemble the O 2 molecules in air to the surface of BiOCl nanosheets. • The surface Bi atoms precisely adsorb and activate benzylamine molecules via interface -C-N···Bi coordination bonds. • Surface Pd sites participated in interface photo-electrons transfer to adsorbed O 2 molecules producing the active ∙O 2 - . • Surface oxygen vacancies, Bi atoms and Pd sites jointly catalyze the precise conversion of benaylimine to imines.

Ultrathin 2D/2D Ti3C2Tx/semiconductor dual-functional photocatalysts for simultaneous imine production and H2 evolution

Abstract: Ultrathin 2D/2D Ti3C2Tx/semiconductor (CdS and Bi2MoO6) dual-functional photocatalysts have been constructed for the oxidative coupling of benzylamines to imines combined with H2 generation under visible light irradiation (λ ≥420 nm). The optimal 2D/2D Ti3C2Tx/CdS sample exhibits high photocatalytic performance toward H2 evolution (219.7 μmol g−1 h−1) and imine production (155.8 μmol g−1 h−1), which is 5 times and 6 times higher than that of pure CdS, respectively. In situ irradiated XPS and photoelectrochemical characterizations reveal that the enhanced photoactivity over Ti3C2Tx/semiconductor heterostructures can be attributed to the facilitated charge separation from the semiconductors to the Ti3C2Tx cocatalyst. A possible reaction mechanism is proposed based on in situ FTIR spectroscopy of benzylamine adsorption and imine product desorption and reaction intermediate detection using in situ ESR. This work provides a systematic strategy to construct ultrathin 2D/2D Ti3C2Tx/semiconductor heterojunctions for photocatalytic synthesis of high value-added products combined with H2 generation.

Au surface plasmon resonance promoted charge transfer in Z-scheme system enables exceptional photocatalytic hydrogen evolution

Abstract: Highly efficient photocatalytic water reduction to evolve hydrogen can be achieved by the construction of Z-scheme systems that mimics natural photosynthesis. However, coupling appropriate semiconductors with suitable water reduction potential still remains challenging. Herein, we report a novel Z-scheme system, based on the Au decorated 5,10,15,20-tetrakis(4-trimethylammoniophenyl) porphyrin tetra(p-toluene sulfonate) functionalized iron-doped carbon nitride. We prepared carbon nitride by varying the amount of iron dopant and then functionalized with porphyrin to obtain heterostructure photocatalyst. Owing to the strong interfacial contact and proper band alignment, a Z-scheme system is fabricated. Finally, we deposited Au nanoparticles over the surface of the as-fabricated Z-scheme system to promote the surface redox properties via efficient charge carrier’s separation and transfer. The 3Au-3 P/30Fe-CN photocatalyst achieved excellent H2 evolution activity by producing 3172.20 µmol h−1 g−1 under UV–visible irradiation. The calculated quantum efficiencies for 3Au-3 P/30Fe-CN photocatalyst at 365 and 420 nm irradiation wavelengths are 7.2% and 3.26%, respectively. The experimentally observed efficiency of our photocatalyst is supported by the density functional theory simulations in terms of the lowest work function and strong electrostatic interaction among the constituents of Z-scheme system.