Cellulose Nanocrystal–ZnO Nanohybrids for Controlling Photocatalytic Activity and UV Protection in Cosmetic Formulation

Abstract

A high-performance semiconductor zinc oxide (ZnO) on melamine formaldehyde-coated cellulose nanocrystals (MFCNCs) was synthesized and evaluated for its application in smart cosmetics. These ZnO@MFCNC hybrid nanostructures were evaluated for their in vitro sun protection factor performance and photocatalytic activity under simulated UV and solar radiation. The photodegradation kinetics of a model pigment (methylene blue) was fitted to the Langmuir–Hinshelwood model. A 4-fold increase in the photocatalytic activity of ZnO@MFCNCs was observed when compared to pure ZnO. This is associated with (i) increased specific surface area provided by the MFCNC template, (ii) confined surface energy and controlled growth of ZnO nanoparticles, and (iii) entrapment of photoinduced charge carriers in the pores of the core–shell MFCNC rod, followed by fast promotion of interfacial e-charge transfer to the surface of the catalyst. The present study demonstrates how an increase in photocatalytic activity can be engineered without the introduction of structural defects or band gap tailoring of the semiconductor. The aqueous-based ZnO@MFCNC hybrid system displayed attractive UV-absorption and photocatalytic characteristics, offering the conversion of this renewable and sustainable technology into intelligent cosmetic formulations.

Amorphous and crystalline cerium(iv) phosphates: biocompatible ROS-scavenging sunscreens

“…The probability of formation and stability of the e − /h + pair determines the photocatalytic properties of the semiconductor, and the rate of e − or h + migration to the surface plays an important role in this process: a lower rate increases the possibility of pair recombination, decreasing catalytic efficiency. The migration rate decreases when there is a narrowing of the band gap, 77 therefore the narrow band gap facilitates the recombination of photogenerated electron–hole pairs. 78 Thus, all other things being equal, NH 4 Ce 2 (PO 4 ) 3 will possess the least photocatalytic activity.…”

Green one-step synthesis of cellulose nanocrystal/ ZnO nanohybrid with high photocatalytic activity

“…Năng lượng vùng cấm của ZnO là 3,3 eV xấp xỉ với TiO 2 (3,2 eV đối với pha anatase) nên ZnO có các đặc tính quang học và quang xúc tác đáng chú ý. Do đó, ZnO cũng được ứng dụng trong nhiều lãnh vực không những trong thiết bị quang học, thiết bị phát hiện tia cực tím, cảm biến khí, pin mặt trời và trong diod tia cực tím laser [2][3][4] mà cả trong ngành y tế và dược phẩm để phân phối thuốc và sản xuất mỹ phẩm. Mặt khác, một trong những điều thu hút sự phát triển của ZnO gần đây là ứng dụng của vật liệu này trong xử lý nước thải nhờ vào khả năng phân hủy các chất ô nhiễm bao gồm thuốc nhuộm hữu cơ trong nước và cũng để loại bỏ kim loại nặng trong quá trình lọc nước thải [5][6][7] .…”

Upcycling discarded cellulosic surgical masks into catalytically active freestanding materials

“…The three -OH groups at the 2-, 3- and 6-position in the anhydroglucose repeating unit act as concomitant reducing and capping agents for metal/metal-oxide nanoparticle immobilization (Musino et al 2021 ). Accordingly, different catalytically active nanoparticles have been deposited onto cellulosic substrates, including zinc oxide (Awan et al 2018 ), palladium (Wu et al 2016 ), platinum (Lizundia et al 2019 ), or gold (Yan et al 2016 ). The synergetic effects arising from the cellulosic substrate and the inherent catalytic activity of metal/metal-oxides open novel opportunities for a variety of applications.…”