Biosynthesized Quantum Dot Size Cu Nanocatalyst: Peroxidase Mimetic and Aqueous Phase Conversion of Fructose

Abstract

Environmentally benign, stable quantum dot size spherical Cu particles with an average size of ∼ 4.5 nm, as measured via transmission electron microscope, were coherently tailored exploiting renewable ethno‐pharmacological Oxalis corniculata plant extract as both reducing plus capping agent. The reliable green aqueous synthesis approach completely excluded the usage of inert atmosphere and harmful chemicals including organic solvents. The ensuing cost effective Cu nanoparticles exhibited excellent intrinsic peroxidase like activity and superior nanozyme behaviour compare to earlier reports with Km value of 0.01426 M and rmax equal to 0.1399 Mmin−1 toward the oxidation of peroxidase substrate H2O2 in presence of o‐phenylenediamine, a paradigm reaction. Significantly, the as‐prepared Cu particles have been proven to be a novel catalyst for feasible selective aqueous phase conversion of fructose to levulinic acid with a maximum yield of ∼ 22.38% at 90°C in the absenteeism of prominent side product(s), auxiliaries and high temperature reaction condition. Lewis acid property and large surface area of the generated nanoscale particles attributed to their excellent catalytic potential introducing a new avenue in the continuous demand for better sensing, biomedical applications and cleaner energy production.

Synergistic Lewis acid-base sites of ultrathin porous Co3O4 nanosheets with enhanced peroxidase-like activity

“…In enzymes-like catalysis reaction, Lewis acid can promote the deprotonation of H2O and the production of zinc-bound hydroxide [20]. Cu nanocatalyst exhibited intrinsic peroxidase-like activity influenced by the synergistic effect of Lewis acid sites and large surface area [21]. The acid and base sites were coexisted in some natural enzyme structure, which greatly affected for catalysis activity and selectivity [22].…”

Copper-based Nanozymes: Properties and Applications in Biomedicine

“…与贵金属 Au、Ag 等元素相比，Cu 是生物体内 的必需元素，也是天然酶活性中心金属元素之一。 它在自然界含量丰富、价格低廉，因此铜基纳米酶 得到了研究者的广泛关注和研究。研究发现无论是 二价铜离子、铜纳米颗粒、氧化铜、铜的金属有机 框架材料还是铜单原子催化剂等都表现出了优异的 酶学特性 [41][42][43] 。2011 年，Chen 等 [44] 发现市售的尺 寸在 30 nm 左右的 CuO 纳米颗粒具有类过氧化物 酶(Peroxidase, POD)活性。随后人们又相继发现 CuS [45][46] 、MOF-199 [47] 、Cu NPs [48][49] 等均表现出了 优异的类 POD 活性， 但这些材料均只表现出单一的 类酶活性。 Peng 等 [50] 以谷胱甘肽为配体合成的超小 铜团簇(Cu NCs)表现出了多重类酶活性--过氧 化氢酶(CAT ) 、超氧化物歧化酶(SOD) 、谷胱甘肽 过氧化物酶(GPx)活性。随着大量无机纳米酶的发 现，科学家逐渐不满足于纳米酶的随机合成。受细 胞色素 P450 的轴向配体配位血红素的启发，Huang 等 [51] 构建了以 FeN5 为活性中心的单原子纳米酶。 而后人们以氮化碳材料、金属氧化物、金属有机框 架材料等为基底制备出一系列铜基单原子纳米酶， 进一步拓宽了铜基纳米酶的范围 [52][53][54][55] 。 本文阐述了铜基纳米酶的分类、酶学特性，及 其在生物医学中的应用。…”