CHẾ TẠO VÀ NGHIÊN CỨU TÍNH CHẤT VẬT LÍ, KHẢ NĂNG QUANG XÚC TÁC CỦA VẬT LIỆU TỔ HỢP g-C3N4/ZnO

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Ngôn ngữ: vie

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Thông tin xuất bản: Tạp chí Khoa học - Trường Đại học Sư phạm Hà Nội: Khoa học Tự nhiên, 2020

Mô tả vật lý: tr.46

Bộ sưu tập: Báo, Tạp chí

ID: 312858

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In this study, g-C3N4/ZnO composites were fabricated using an ultrasound mixing method. The physical properties as well as the photocatalytic properties of the materials have beenstudied by several techniques such as X-ray diffraction, scanning electron microscopy SEM, ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy PL. The X-raydiffraction patterns show that the two component phases of the composite material are well crystallized, with no mutual influence on the crystal structure. SEM images show that ZnOnanoparticles are well dispersed on the surface of g-C3N4 nanosheets, facilitating the process of exchange of charges between two component phases. The intensity of fluorescence spectra decreases as the concentration of ZnO in the composites increases, indicating a decrease in the electron-hole recombination rate facilitating the photocatalytic process. Photocatalytic process under the irradiation of Xenon lamps show a higher photocatalytic efficiency of compositesamples compared to both ZnO and g-C3N4. Composite samples CZ7-3 and CZ6-4 show the largest photocatalyst efficiency, decomposing 100% RhB in solution after 90 minutes ofillumination by Xenon lamps. This can be explained by the decrease of the electron-hole recombination rate as observed in the fluorescence spectra and good contact between twocomponent phases as in Sem images.Trong nghiên cứu này, vật liệu tổ hợp g-C3N4/ZnO đã được chế tạo bằng phương pháp trộn cơ học hai thành phần. Tính chất vật lí cũng như tính chất quang xúc tác của vật liệu đã được nghiên cứu thông qua các phép đo như nhi ễu xạ tia X, chụp ảnh hiển vi điện tử quét SEM, phổ hấp thụ tử ngoại - khả kiến, phổ huỳnh quang PL. Giản đồ nhiễu xạ tia X cho thấy hai pha thành phần của vật liệu tổ hợp kết tinh tốt, không có sự ảnh hưởng lẫn nhau về cấu trúc tinh thể. Ảnh SEM cho thấy các hạt nano ZnO phân tán tốt trên bề mặt các tấm g-C3N4, thuận lợi cho quá trình trao đổi điện tích giữa hai pha thành phần. Cường độ huỳnh quang giảm dần khi tăng nồng độ ZnO trong vật liệu tổ hợp, chỉ ra sự suy giảm tốc độ tái hợp điện tử - lỗ trống, thuận lợi cho quá trình quang xúc tác. Kết quả nghiên cứu quá trình quang xúc tác dưới sự chiếu xạ của đèn Xenon cho thấy các mẫu tổ hợp đều có khả năng quang xúc tác lớn hơn của hai pha thành phần. Mẫu tổ hợp CZ7-3 và CZ6-4 cho hiệu suất quang xúc tác lớn nhất, phân hủy 100% RhB trong dung dịch sau 90 phút chiếu sáng đèn Xenon. Điều này được giải thích do sự suy giảm tốc độ tái hợp điện tử - lỗ trống như quan sát thấy trong phổ huỳnh quang.

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