The crystal plane effect on the peroxidase-like catalytic properties of Co3O4 nanomaterials

Abstract

Nanomaterials as enzyme mimics have received considerable attention as they can overcome some serious disadvantages associated with the natural enzymes. In recently developed Co3O4 nanoparticles as peroxidase mimics, the influence of the crystal plane on the catalytic performance has not been demonstrated. In order to better understand their crystal plane-dependent catalysis, the present study was initiated using three different Co3O4 nanomaterials, nanoplates, nanorods and nanocubes, as model systems. According to HRTEM, the predominantly exposed planes of nanoplates, nanorods and nanocubes are {112}, {110} and {100} planes, respectively. The catalytic activities were explored by using H2O2 and different organic substrates as the substrates of peroxidase mimics, and were investigated in-depth by steady-state kinetics and electrochemistry methods in depth. The results show that the peroxidase-like activity increases from nanocubes to nanoplates, via nanorods. The effect of external conditions such as pH and temperature on the three nanomaterials is the same, which indicates that the difference in their catalytic activities originates from their different shapes. The peroxidase-like catalytic activities of Co3O4 nanomaterials are crystal plane-dependent and follow the order: {112} ≫ {110} > {100}. The three crystal planes have different arrangements of surface atoms, thus exhibiting different abilities of electron transfer, which induce their different peroxidase-like catalytic activities. This investigation clarifies that the peroxidase-like activity of Co3O4 nanomaterials can be enhanced by shape control. These findings show that Co3O4 nanomaterials can serve as catalyst models for designing other catalysts.

Synthesis of a mixed valence state Ce-MOF as an oxidase mimetic for the colorimetric detection of biothiols

“…Based on Lineweaver-Burk plots, the K m and V max of MVCM were calculated to be 0.37 µM and 5.5 70 µM s -1 , respectively. Compared to the previous report 10 with 3.8 µM and 0.7 µM s -1 , MVCM had higher affinity and activity for TMB, this maybe due to the large surface areas of MVCM and the π-π stacking interaction between MVCM and TMB. It means that the MVCM first binds and reacts with the TMB, then releases the product oxTMB.…”

“…On the basis of the excellent catalytic activity of MVCM, a 10 colorimetric approach to detect biothiols in serum samples was established. As illustrated in scheme 2, first, the MVCM was added to TMB in NaAc buffer to generate blue color oxTMB.…”

Shape Engineering of Oxide Nanoparticles for Heterogeneous Catalysis

“…Tests for H 2 O 2 decomposition on Co 3 O 4 nanoplates, nanorods, and nanocubes show clear shape-dependenta ctivity with the order {112} @ {110} > {100}. [84] This peroxidase-like property requires two different oxidation states, that is, Co 2 + /Co 3 + .T he surfacel ayer of the {100} planeso nly contain Co 2 + cations, and Co 3 + cations are present in the sublayer;t he {112} and{ 110} planesc ontain both Co 2 + and Co 3 + cations, which makes the nanoplates and nanorods more active than the nanocubes.…”

Evaluation of the oxidase like activity of nanoceria and its application in colorimetric assays

“…NP-based enzyme mimetics offer advantages in terms of cost, stability, ease of production and tenability of catalytic activity. Examples of NP systems with enzyme like activity include: nano-gold [16], ferromagnetic materials such as Fe 3 O 4 [17], Co 3 O 4 [18], sheet like-FeS nanostructures, CeO 2 [19], AgM (silver supported metallic nanoparticles), mesoporous silica encapsulated Pt [13]and metallic NPs supported graphene oxide [12,20]. Implementation of these materials in analytical and bioanalytical platforms could rouse development of a new generation of devices with significantly enhanced performances in stability and robustness compared to their enzyme counterparts.…”