Designing Layered Double Hydroxides/Oxides Based On Atomic Layer Deposition Applied As Peroxidase Mimics

Atomic layer deposition(ALD)is an advanced coating technology that grows layer by layer in the form of a single atomic film.The thickness of the deposited film is uniform and controllable at a lower temperature.It has been widely used in many fields such as catalysis,absorbing,biosensmg,and electrochemistry,and has achieved very satisfactory results.Furthermore,as an efficient film preparation technology,ALD has many significant advantages in the optimization of material composition,the design of new nanomaterials,and the preparation of uniform coatings.In this paper,a series of metal oxides and layer double hydroxides(LDH)were prepared by using the high uniformity and controllability of ALD process.A simple and free-lable colorimetric method was established and employed in detecting hydrogen peroxide and glucose.The main contents of this article are as follows:1.In this paper,we succeed in preparing a CuNiAl LDH hierarchical structure by an atomic-layer-deposition assisted method.The Al2O3-coated NIC2O4(Al2O3@NiC2O4)structures were obtained by an ALD approach using the as-prepared NIC2O4 nanowires as the starting substrate.Al2O3/Ni composites were prepared by annealing Al2O3/NiC2O4 at 350? for 1 h under a mixture ot H2/Ar flow in a tube furnace.Finally,CuNiAl LDH was obtained by an in situ growth technique.Through scanning electron microscopy and transmission electron microscopy,we found that CuNiAl LDH showed homogeneous and dispersed nanoflakes on the tube.The unique structures of CuNiAl LDH endowed them with the excellent intrinsic peroxidase mimics activity and used to detect H2O2 and glucose.The glucose detection with a wide linear range(10-200 ?M)and low detection limit(2.9 ?M),the linear fitting equation is A=0.00048 Cglucose+0.01815(mM).with a correlation coefficient of 0.9979.The established method was successfully used to detect glucose in juice samples with satisfying results.2.In this work,an atomic-layer-deposited Al2O3 induced LDH growth strategy was proposed to facilely prepare carbon fiber supported ultrathin CuAl LDH nanosheet(CF@CuAl-LDH).Through TEM and SEM,we found that the uniform Al2O3 coating on carbon fiber(CF)was obtained by an atomic layer deposition(ALD)method and could be used as a pinpoint inductive layer to turn into ultrathin CuAl LDH nanosheet via a hydrothermal treatment.The obtained CF@CuAl-LDH exhibited the superior enzyme mimic activity due to the unique structural features which could offer large ion-accessible surface,more active sites area and efficient electron transfer pathways.Based on these,a simple and sensitive tree-label biosensor was developed for colorimetric determination of H2O2 and glucose.The established method can be applied to the glucose detection with a wide linear range(5-100 ?M)and low detection limit(3.8 ?M)3.In this work,carbon nanotube coated by NiO and Fe2O3 nanocomposites(NiO/Fe2O3/CNT)has been synthesized by an ALD method.The peroxidase-like investigations indicate that the obtained NiO/Fe2O3/CNT nanocomposites exhibit high-efficient peroxidase-like activity.On the basis of high peroxidase-like activity,a simple and facile approach was developed for the colorimetric detection of H2O2 and glucose.The glucose detection with a wide linear range(5-60 ?M)and low detection limit(2.2 ?M).