Morphology and Size-Dependent Visible-Light-Driven Photocatalytic Hydrogen Evolution of Porphyrin Assemblies

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MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.210

Morphology and Size-Dependent Visible-LightDriven Photocatalytic Hydrogen Evolution of Porphyrin Assemblies Yong Zhongb, Yaoqing Hub, Jiefei Wangc, Jinghan Wangb, Xitong Renb, Jiajie Sun*,a and Feng Bai*,b a

School of Physics and Electronics, Henan University, Kaifeng 475004, China

b Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, School of Materials Science and Engineering, and Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng 475004, China

c International Joint Centre for Biomedical Innovation, School of Life Sciences, Henan University, Kaifeng 475004, China

CORRESPONDING AUTHORS *Email: [email protected] (J. Sun) *Email: [email protected] (F. Bai)

ABSTRACT

Photocatalytic water splitting to form hydrogen can effectively alleviate energy and environmental problems attracting wide attention. However, the current photocatalysts have low photocatalytic efficiencies due to the narrow absorption spectrum, which is far from the actual application requirements. Herein, we use the as-prepared zinc porphyrin selfassemblies to visible-light-drive photocatalytic hydrogen evolution with Pt as the cocatalyst and ascorbic acid (AA) as the sacrificial agent. The results exhibit morphology-dependent performance and hexagonal stacks achieved optimal H2 evolution rate (47.1 mmol/h/g), then followed by nanodiscs, nanorod and tetragonal stacks, meanwhile the nanorods with different

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aspect ratios show size-dependent properties. The UV-vis absorption and photoluminescence spectra and the shortening of decay time of the corresponding ZnTPyP aggregates reveal that the well-defined self-assembled porphyrin networks are J-aggregation and boost efficient energy transfer with respect to monomer. Such porphyrin self-assemblies are standing for one of the most promising photosensitizers in photocatalysis field and provide an important reference for designing the next generation of hydrogen production.

INTRODUCTION The shortage of fossil fuels and environmental pollution have become a key issue that constrains the sustainable development of economic society. Hydrogen (H 2) is known as an ideal green energy with a renewable, energy dense and efficient energy carrier to alleviate these issues [1]. Photocatalytic water splitting to form hydrogen directly converts solar energy into hydrogen energy which considered to be one of the most attractive potential solutions [2]. However, the photocatalytic efficiency is limited due to the narrow absorption spectrum of semiconductor catalyst [3]. The chromophore is one of the most important facto