ZnO Crystals Research Articles

Characterization of GO Added ZnO Crystal Growth Using Electric Current Heating Method

ZnO has attractive and great properties especially in the fields of photonics, electronics and optics and it is widely used in the manufacturing industry of photodetectors, laser diodes and gas detectors. Therefore, various methods have been carried out to produce ZnO crystals and one of them is the Electric Current Heating method. Electric Current Heating (ECH) method is a fabrication technique applied in researches to grow ZnO crystal on a ceramic bar. This method is preferred because of it is easy to operate in laboratory, low growth temperature and also low cost. In this research, by using powder metallurgy process, Graphene Oxide/GO (in various weight percentage) added into ZnO was pelletized in a compaction die with dimension of 14.95 mm x 30 mm x 40 mm and pressure of 4 bar. The pellet green body was then sintered at 1100 °C with rate 10.0 °C/min for 3 hours. The sintered GO added ZnO ceramic was cut into ceramic bar with dimensio of 13mm x 2mm x 2mm. ECH with current 3 A and applied voltage of 30 V was used to heat the ceramic bar to produce crystals. Under scanning electron observation, it was found different crystal-like structures for each percentage GO addition. UV-Vis measurement has shown that each crystal-like structure of a GO added ZnO has own degree of energy absorbsion because of different band gap. Addition GO into ZnO would increase band gap of pure ZnO.

Doping ZnO Crystals with Gold during Their Growth by the Vapor‒Liquid‒Crystal Method

Doping ZnO Crystals with Gold during Their Growth by the Vapor‒Liquid‒Crystal Method

Characterization of ZnO Crystals of Various Geometries Grown by Mist Chemical Vapor Deposition on a c‐Plane Sapphire Substrate

ZnO nanowires, nanowalls, and thin‐film‐like crystals are grown simultaneously on a c‐plane sapphire substrate by mist chemical vapor deposition (mist‐CVD) at a high growth temperature. Mist‐CVD is expected to be a potentially low‐environment‐impact and low‐cost crystal growth technique. Using mist‐CVD techniques, a spatial distribution of crystal growth is obtained owing to equipment configurations that enable the simultaneous fabrication of ZnO crystals of various geometries. Their crystallinity and photoluminescence properties are examined to clarify their potential applications and to investigate low‐cost photonic applications based on these properties.

Crystal Al-Doped ZnO Thin-Film Preparation by Sputtering Deposition using a Mixed-Powder Target

Al-doped ZnO films were prepared by sputtering deposition using mixtures of Al2O3 and ZnO powder targets. The film quality depended on the conditions of the target powder. The deposition rate, crystallinity, and transparency of films prepared with new, pressed powder targets were higher than those prepared with used, nonpressed powder targets. In addition, we found that pressurizing the new-powder target and increasing the substrate temperature resulted in thin films with high transparency and electrical conductivity

Insights into the Electronic, Optical, and Anti-Corrosion Properties of Two-Dimensional ZnO: First-Principles Study

The electronic, optical, and anticorrosion properties of planer ZnO crystal and quantum dots are explored using density functional theory calculations. The calculations for the finite ZnO quantum dots were performed in Gaussian 16 using the B3LYP/6-31g level of theory. The periodic calculations were carried out using VASP with the plane wave basis set and the PBE functional. The subsequent band structure calculations were performed using the hybrid B3LYP functional that shows accurate results and is also consistent with the finite calculations. The considered ZnO nanodots have planer hexagonal shapes with zigzag and armchair terminations. The binding energy calculations show that both structures are stable with negligible deformation at the edges. The ZnO nanodots are semiconductors with a moderate energy gap that decreases when increasing the size, making them potential materials for anticorrosion applications. The values of the electronic energy gaps of ZnO nanodots are confirmed by their UV-Vis spectra, with a wide optical energy gap for the small structures. Additionally, the calculated positive fraction of transferred electrons implies that electron transfer occurs from the inhibitor (ZnO) to the metal surface to passivate their vacant d-orbitals, and eventually prevent corrosion. The best anti-corrosion performance was observed in the periodic ZnO crystal with a suitable energy gap, electronegativity, and fraction of electron transfer. The effects of size and periodicity on the electronic and anticorrosion properties are also here investigated. The findings show that the anticorrosion properties were significantly enhanced by increasing the size of the quantum dot. Periodic ZnO crystals with an appropriate energy gap, electronegativity, and fraction of electron transfer exhibited the optimum anticorrosion performance. Thus, the preferable energy gap in addition to the most promising anticorrosion parameters imply that the monolayer ZnO is a potential candidate for coating and corrosion inhibitors.

Origin of microscopically coupled ferromagnetic Cu-ions in a distorted system of Cu-doped ZnO and their synchrotron-based electronic structures

Spintronics-based studies have produced significant attention in the last decade while claiming the observation of room temperature ferromagnetism (RTFM). Nevertheless, there is a lack of consensus on a mechanism responsible for this phenomenon. In this study, we focus on Cu-doped ZnO (ZCO) to understand the microscopic origin of RTFM and the role of different oxidation states of Cu in RTFM. We have performed different spectroscopic techniques using synchrotron facilities. The values of spin-moment obtained from x-ray magnetic circular dichroism sum-rule truly exhibit a ferromagnetic interaction in the nanocrystalline powder of ZCO with ∼0.58 μB for 5% of Cu concentration in the total fluorescence yield mode. Such an enhanced magnetization is attributed to the presence of Cu2+, which is mainly localized in the bulk region. Cu in ZCO is mostly dominated by the presence of Cu2+. This is clearly reflected by the profiles of x-ray photoemission spectroscopy. Consequently, the weakly magnetized total electron yield mode is attributed to a state of magnetic frustration as the majority of Cu3+ is found on the surface. Some of these Cu3+ when come in the vicinity of Cu2+ ions result in a highly correlated state of double exchange mechanism, which is the microscopic origin of RTFM in ZCO. The coupling between Cu2+-Cu3+ is mediated via oxygen vacancies (VO), the presence of which is confirmed through the features of electron energy loss spectroscopy over different edges. The confirmation of VO is also supported by the deconvolution of E2high-phonon in the Raman spectra. Moreover, the defects in the local electronic structures of ZCO are demonstrated by the deconvoluted spectra of Cu L3 x-ray absorption spectroscopy. The images obtained from high-resolution transmission electron microscopy confirm the incorporation of Cu into the wurtzite crystal of ZnO. A clear enhancement in magnetization upon an increase in carriers of Cu in ZCO indicates carrier-induced ferromagnetism. Cu2+ and VO are the two attributes of RTFM in ZCO.

An in vitro cytotoxicity study on PANI/ZnO nanocomposites against HCT- 116 cancer cells using MTT assay

Polyaniline/ZnO nanocomposites were synthesized with different weight percentage of ZnO (20%, 40%, 60%, and 80%) using an in situ chemical polymerization method. The prepared composite samples were characterized by FT-IR, XRD, TEM, SEM with EDAX, UV-Vis, PL, electrical conductivity, photocatalytic properties, antibacterial and anticancer activity. The presence of functional groups in PANI-ZnO NCs is identified by FTIR spectral analysis. X-ray diffraction patterns show that the nanocomposites exhibit preferential orientational growth along the (002) plane with a hexagonal wurtzite structure. The intensity of the maximum reflection (101) increases with increasing ZnO doping concentrations. The TEM analysis indicates that the spherical shape,the particle size was found to be 36.8 nm. SAED pattern closely matched the peaks of the XRD pattern, confirming that the relevant SAED patterns correspond to hexagonal Wurtzite crystals of ZnO. SEM image shows a spherical morphology and ZnO nanoparticles are homogeniously mixed with PANI matrix. EDAX analysis showed the presence of Zn, C and O.UV-vis absorption spectra reveals increasing wavelength leads to the redshift in which there is a strong interaction between PANI and PANI/ZnO. The band gap energy of PANI/ZnO NCs is decreased to 1.30 eV by adding different concentrations of ZnO. PL analysis showed that the addition of ZnO dopants reduced the bandgap and increased oxygen defect vacancies of PANI/ZnO composites. An increase in ZnO content in the PANI matrix was also seen to cause a decrease in electrical conductivity. This alteration might be connected to ZnO’s doping and dedoping activity in the PANI matrix. Photocatalytic activity of 80 wt%ZnO-doped PANI-NPs through the degradation of methylene blue (MB) pigment studied under UV-A light and had detected 95% of degradation throughout 260 min. The lowest bandgap of 80 wt% ZnO shows the highest photocatalytic MB degradation performance. PANI/ZnO nanocomposite with high concentration of ZnO had good antibacterial activity against both P. aeruginosa and S. aureus. An in vitro study was used to evaluate the cytotoxic effects of PANI and PANI/ZnO NPs on the HCT-116 cell line. The results of the MTT test reveal that PANI/ZnO NPs have a significantly greater cytotoxic effect on the HCT-116 cell line than PANI.

Self-cleaning and UV-blocking cotton – Fabricating effective ZnO structures for photocatalysis

This study comprehensively examines the relationship between synthesis conditions that affect the morphologies of ZnO crystals and, therefore, the resulting properties of ZnO-coated self-cleaning and UV blocking textiles. Although the current literature presents several individual recipes, this study uniquely identifies and documents the impact of different processing methods and additives on crystal morphology within one complete synthesis protocol—that is, NaOH concentration, microwaving duration, and NH4OH additive quantity. Consequently, we suggest a simple and surfactant-free microwave-assisted method of forming ZnO coating with a distinctive flower-like morphology and high surface coverage, with demonstrated optimal self-cleaning performance: a solution of 66 ml of 0.1 M NaOH, 33 ml of 0.2 M of ZnAc dissolved in EtOH, and 2 ml of NH4OH microwaved for 5 min. The efficacy of ZnO-coated cotton in ultraviolet (UV) blocking was verified with UV protection factor calculations, reaching a near-complete UV blocking capability (as high as 99.93 % for UV-B). The evaluation of photocatalytic self-cleaning performance involved monitoring the discoloration of coffee and methylene blue (MB) stains under 1 Sun, using the innovative photo analysis-based method. The MB dye degradation efficiency of the best-performing samples reached 73 % within the first hour of 1 sun exposure, which is double the speed reported in related studies. The results confirm that flower-like ZnO coating, produced through our simplified protocol, is a viable option for the development of UV-resistant and self-cleaning textiles.

Characterizations of pure and eu-doped ZnO aerogels nanostructures elaborated by a modified sol gel process

Herein we report on the structural and optical properties of pure and Eu-doped (3% at.) ZnO aerogels nanostructures (ZnO-ans) synthesized by sol-gel associated with drying at supercritical conditions of isopropanol (254 °C, 54 bars). The samples were investigated using X-ray diffraction (XRD), SEM, UV-visible spectroscopy, FTIR and photoluminescence (PL). XRD studies exhibit the formation of a high crystal quality ZnO wurtzite hexagonal structure. The UV-visible measurements point out that the absorption intensity and the band gap energy increase after Eu-doping. FTIR analysis confirms the formation of ZnO phase and reveals a shift toward longer wavenumber of the Zn-O absorption band after Eu -doping. SEM images show that Eu3+ ions lead to change the morphology of ZnO crystalline from pastille to sphere. PL measurements reveal a decrease of UV luminescence intensity and an increase of the visible one due to Eu-doping.

Cost-effective efficient materials for dye degradation using non-aqueous sol-gel route.

In the present studies, the synthesis of pure ZnO nanoparticles and Mg and S-doped ZnO particles were carried out using a non-aqueous sol-gel method. The synthesized nanoparticles (NPs) are characterized using XRD, FESEM, EDX, FTIR, UV-Vis-DRS, XPS, PL, and BET surface area analysis. X-ray diffraction (XRD) techniques were used to examine the crystallization of ZnO, Mg-ZnO, and S-ZnO samples. The Mg-ZnO and S-ZnO samples exhibit significant c-axis compression and smaller crystallite sizes as compared to undoped ZnO. The optical band gap of Mg-ZnO and S-ZnO NPs were found to be 2.93eV and 2.32eV, respectively, which are lower than that of ZnO NPs (3.05eV). The S-doped ZnO resulted in the homogenous distribution of sulfur ions in the ZnO lattice crystal. XPS analysis revealed that the doped S element was mostly S4+ and S6+. A systematic evaluation has been conducted to assess the influence of several operational parameters, including doped/undoped stoichiometry, solution pH, catalyst dosage, and radical trapping experiment, on the photocatalytic degradation of Rhodamine 6G (Rh 6G) dye. Furthermore, we investigated the photocatalytic degradation activity of ZnO, Mg-ZnO, and S-ZnO samples with aquoues solution of 5ppm Rhodamine 6G (Rh 6G) at room temperature. Results indicated that pure ZnO nanoparticles have the highest photocatalytic degradation rate constant (0.00344min-1), compared to the samples Mg-ZnO (0.00104min-1) and S-ZnO (0.00108min-1) with Rh 6G dye in presence of visible light emitting diode (Vis-LED) source at room temperature. The enhanced visible light photocatalytic activities of pure ZnO NPs were attributed to their superior surface properties (18.30 m2/g) and effective electron-hole separation.

Green synthesis of ZnO nano-crystals using Chenopodium album L. Leaf extract, their characterizations and antibacterial activities

We present an effective, simple and eco-friendly method for the green synthesis of ZnO nano-crystals. An aqueous extract of Chenopodium album leaf was used as a biological reducing agent for the fabrication of ZnO nano-crystals from the zinc sulphate heptahydrate. The as-prepared and annealed powder samples were characterized using advanced techniques. The results confirmed the presence of ZnO crystals with a broad size distribution, whose crystallinity was noticed to improve substantially after the annealing. Further, in antibacterial activity test of ZnO nano-crystals performed on Escherichia coli and Staphylococcus aureus microorganisms, inhibitory effect was found to increase with concentration. Compared to Gram-positive bacteria, ZnO nano-crystals showed more resistance to Gram-negative bacteria. This green synthesis route of ZnO nano-crystals is novel and aims to reduce the use of toxic chemicals in fabricating the nanoparticles of functional oxides, which have a wide range of potential applications in general and biomedical science, in particular.

Low Temperature Calcination of TiO2 and ZnO Particle Film and Evaluation of Their Photocatalytic Activity

<p>In this study, TiO<sub>2</sub>, ZnO, and TiO<sub>2</sub>/ZnO films were prepared under low calcination temperature and characterized to observe their properties related to photocatalytic performance. The samples were prepared by mixing the gel phase of ZnO precursor, TiO<sub>2</sub> anatase powder, triton-x 100, and acetylacetone to produce a paste form for the deposition process. The resulting paste was then deposited by screen printing onto a glass substrate and subjected to calcination at 250C to facilitate the ZnO crystallization and remove other additive materials. XRD analysis confirms that the formation of ZnO and TiO<sub>2</sub> crystals was assisted, although their crystallinity was lower than corresponding particulate forms. The lower crystallinity seems to be related by additive materials remains. The surface morphology of each sample was observed by scanning electron microscopy (SEM) imaging, Brunauer–Emmett–Teller (BET), and contact angle examination. Interestingly, both TiO<sub>2</sub> and ZnO layers tend to have a hydrophobic surface meanwhile TiO<sub>2</sub>/ZnO has a hydrophilic surface. BET analysis revealed that ZnO has the highest specific surface area due to a nanosized. FTIR spectra confirmed the presence of appropriate chemical bonds in the ZnO and TiO<sub>2</sub> and other additive materials, such as alkyl groups. The photoluminescence (PL) spectrum shows a blue emission associated with intrinsic defects such as vacancies and interstitials of Zn and Ti in all samples. Differences in the photocatalytic performance of film and particulate form for each material were observed and analyzed. All samples' structures, morphology, and PL characteristics were then correlated to their photocatalyst behavior for methylene blue degradation.</p>

Bringing the photoplastic effect in ZnO to light: A photoindentation study on pyramidal slip

The external light environment has been reported to have a pronounced influence on the dislocation-based plasticity in various inorganic semiconductors. Herein, with a specific focus on the pyramidal slip in wurtzite structures, photoindentation tests were performed on the (0001) plane of ZnO crystal to activate the pyramidal slip and evaluate the effects of light on dislocation behaviors. Statistical analyses of the first pop-in events suggested that the corresponding maximum shear stresses in darkness were slightly smaller than those in 405 nm light, indicating a minor effect of light on dislocation nucleation event. Regarding nanoindentation creep tests, light illumination was found to suppress the indentation depth. Further transmission electron microscopy observations demonstrated that indentation-induced pyramidal dislocations were present deeper in darkness than in 405 nm light, revealing a suppressive effect of light illumination on the pyramidal slip in ZnO for the first time.

Surface oxygen vacancies prompted the formation of hydrated hydroxyl groups on ZnOx in enhancing interfacial catalytic ozonation

Herein, a highly dispersed catalyst (ZnOx-500) was synthesized for heterogeneous catalytic ozonation (HCO), which had a simple ZnO crystal phase but riched in oxygen vacancies (OVs). The O3/ZnOx-500 system exhibited both superior catalytic activity and stability after several cycles, providing a promising strategy for atrazine (ATZ) removal. The strong inhibition of phosphoric acid validated the dominant role of the hydroxyl group (−OH) from water molecule (H2O) dissociation on the zinc site near OVs. Density functional theory calculation further revealed that OVs on (100) and (101) planes could make more zinc sites exposed and facilitate the formation of hydrated −OH, which was easier to approach O3 for its decomposition to generate hydroxyl radical (•OH). This work revealed the intrinsic relationship between OVs and hydrated −OH in an aqueous solution, providing new insight into the solid-liquid interface mechanism of HCO.

CuO-ZnO nanocomposites-based thin films: Characterization, physical properties and sunlight photocatalytic degradation of organic pollutants

One of the most commonly employed techniques for boosting photocatalytic efficiency by separating photo-induced electrons and holes is the formation of heterojunctions. The photocatalytic activity of CuO-ZnO nanocomposites-based thin films was investigated in this work for the decomposition of a model pollutant, methylene blue (MB), under sunlight irradiation. The spray pyrolysis method was utilized to produce nano-sized pure CuO and ZnO thin films, as well as CuO-ZnO nanocomposite thin films with varied molar ratios (Cu:Zn 1:3, 1:1, and 3:1). The structural and optical properties of the prepared materials were carefully studied. Contact angle measurements were used to determine the samples' wetting properties. XRD and Raman spectra confirmed the hexagonal würtzite and cubic structures of ZnO and CuO crystals in the different heterostructures. SEM images demonstrated the growth and distribution of the grains, with some spherical or plate-like nanostructures. The composition of the synthesized nanocomposites is confirmed by EDX analysis. UV-Vis investigations indicate that the optical band gaps are considerably impacted by the composition of nanocomposites. PL measurements confirmed a large number of defects in the synthesized nanocatalysts. These data also reveal that the formation of p-n heterojunctions prevented photogenerated carriers from recombining. The photocatalytic activity of the prepared CuO-ZnO nanocomposites was found to be greater than that of individual semiconductors. A possible mechanism and involvement of radicals in photocatalytic dye degradation were also proposed. As a result, the produced nanocomposite thin films might be beneficial for environmentally friendly and energy-saving wastewater treatment.

High-order harmonic generation of ZnO crystals in chirped and static electric fields

High harmonic generation in ZnO crystals under chirped single-color field and static electric field are investigated by solving the semiconductor Bloch equation (SBE). It is found that when the chirp pulse is introduced, the interference structure becomes obvious while the harmonic cutoff is not extended. Furthermore, the harmonic efficiency is improved when the static electric field is included. These phenomena are demonstrated by the classical recollision model in real space affected by the waveform of laser field and inversion symmetry. Specifically, the electron motion in k-space shows that the change of waveform and the destruction of the symmetry of the laser field lead to the incomplete X-structure of the crystal-momentum-resolved (k-resolved) inter-band harmonic spectrum. Furthermore, a pre-acceleration process in the solid four-step model is confirmed.

Cathodic electrophoretic deposited HA-rGO-ZnO ternary composite coatings on ZK60 magnesium alloy for enhanced corrosion stability

HA-rGO-ZnO ternary composite coatings were successfully prepared on ZK60 magnesium alloy using cathodic electrophoretic deposition method. XRD analysis proved the addition of ZnO nanoparticles induced a significantly reduced crystallinity in hydroxyapatite and the tensile strain values of HA-rGO-ZnO composite coatings gradually decreased as the content of ZnO increased. SEM analyses revealed that the HA and ZnO nanoparticles were anchored on rGO nanosheets and a closely-packed network of recrystallization needle-like ZnO and mineralization HA crystals was formed on the surface of HA-rGO-ZnO coated sample. The resulting composite coating exhibited a uniform and compact HA-rGO-16ZnO composite coating, with well adhered to the ZK60 magnesium alloy substrate. The HA-rGO-16ZnO coated sample exhibited the highest corrosion resistance with lowest icorr (1.12 × 10−6 A/cm2) and the highest Ecorr (−1.43 V/SCE) value when compared to HA-rGO-14ZnO and HA-rGO-18ZnO samples after immersion in a SBF for 10 min. Compared to HA-rGO-ZnO coated samples after 10 min of immersion in SBF, HA-rGO-ZnO coated samples after 3 days of immersion in SBF exhibited a remarkably improved corrosion resistance and rapid inducing of the apatite layer precipitated on the surface of the composite coatings. The microstructure and composition for the coated samples after 3 days of immersion in SBF also confirm that the presence of a apatite layer on the composite coatings. HA-rGO-18ZnO coated samples after 3 days of immersion in SBF showed the lowest icorr value, which indicating HA-rGO-18ZnO ternary composite coatings dramatically improved the formation ability of the apatite layer and led to an enhancement in the bioactivity. Accordingly, it is believed that the HA-rGO composite coating incorporated with ZnO will be a potential candidate for bone biomedical applications.

Spin selection in atomic-level chiral metal oxide for photocatalysis

The spin degree of freedom is an important and intrinsic parameter in boosting carrier dynamics and surface reaction kinetics of photocatalysis. Here we show that chiral structure in ZnO can induce spin selectivity effect to promote photocatalytic performance. The ZnO crystals synthesized using chiral methionine molecules as symmetry-breaking agents show hierarchical chirality. Magnetic circular dichroism spectroscopic and magnetic conductive-probe atomic force microscopic measurements demonstrate that chiral structure acts as spin filters and induces spin polarization in photoinduced carriers. The polarized carriers not only possess the prolonged carrier lifetime, but also increase the triplet species instead of singlet byproducts during reaction. Accordingly, the left- and right-hand chiral ZnO exhibit 2.0- and 1.9-times higher activity in photocatalytic O2 production and 2.5- and 2.0-times higher activities in contaminant photodegradation, respectively, compared with achiral ZnO. This work provides a feasible strategy to manipulate the spin properties in metal oxides for electron spin-related redox catalysis.

Investigations on structural, photoluminescent, and photometric properties of poly(vinyl alcohol)-capped Mn doped-ZnO nanoparticles for white light emission

In this paper, luminescent Mn-doped ZnO nanoparticles (NPs) and poly(vinyl alcohol) (PVA) capped Mn-doped ZnO nanocomposite materials were successfully synthesized by the chemistry route. The studied results indicate that the diffraction peaks of Mn-doped ZnO NPs (2, 4, and 7% Mn) are slightly shifted to the lower 2θ degree angle compared to undoped-ZnO NPs. In contrast, PVA capped Mn-doped ZnO nanocomposite shows a systematic shift of X-ray diffraction (XRD) peaks at larger diffraction angles. These samples fluoresce strongly in the visible wavelength of 380–700 nm. The near-infrared (NIR) emission bands in the 740 nm–1100 nm range are due to the shift of XRD peaks diffraction and the transition between defect states within the ZnO crystal. Photometric and chromatic parameters of PVA capped-2%Mn doped-ZnO NPs are CIE (x, y) ≈ (0.3769, 0.3987), CCT ≈ 4238 (K), Duv = 0.0110, CRI (Ra) = 80, CQS = 84, LER = 164 (lm/Wotp), and S/P ratio = 1.70. Luminescent PVA capped ZnO NPs possess CIE (x, y) ≈ (0.3598, 0.3748), CCT ≈ 4592 (K), Duv = 0.0057, CRI (Ra) = 85, CQS = 87, LER = 207 (lm/Wotp), and S/P ratio = 1.83. The studied results indicate that these luminescent materials are suitable for developing a white light emission layer in the structure of light-emitting devices.

Piezoelectric Zinc Oxides with High Polar Facets Ratios for Mechanically Controlled RAFT Polymerization†

Comprehensive SummaryMechanoredox chemistry that uses highly polarized piezoelectric materials as mechanoredox catalysts to promote redox reactions has emerged recently. It provides an alternative approach alongside the existing polymerization methods. Despite recent accomplishments, determining the quantitative relationship between the structure of ZnO and its catalytic performance for polymerization is still challenging. Herein, we prepared various ZnO crystals with different polar facets ratios to achieve efficient mechanically induced reversible addition‐fragmentation chain transfer polymerization (mechano‐RAFT). ZnO prepared from Zn(NO3)2 showed a high polar facet ratio of 1.66 and offered the highest catalytic activity among all ZnO samples. A near‐quantitative initiator efficiency of 99.5% and narrow molecular weight distribution were achieved for the polymerization of n‐butyl acrylate. Furthermore, the high chain‐end fidelity and chain extension capability were also evidenced by MALDI‐TOF MS and GPC analysis. This work highlighted the significant contribution of polar facets in ZnO to its catalytic activity and will guide the design of mechanoredox catalysis with superior catalytic performance in the future.