Atomic Layer Deposition Seeded Growth of Rutile SnO₂ Nanowires on Versatile Conducting Substrates

Abstract

Extended and oriented rutile nanowires (NWs) hold great promise for numerous applications because of their various tunable physicochemical properties in air and/or solution media, but their direct synthesis on a wide range of conducting substrates remains a significant challenge. Their device performance is governed by relevant NW geometries that cannot be fully controlled to date by varying bulk synthetic conditions. Herein, orientation engineering of rutile SnO2 NWs on a variety of conducting substrates by atomic layer deposition (ALD) seeding has been investigated. The seeded growth controls the nucleation event of the NW, and thicknesses and crystallographic properties of seed layers are the key parameters toward tuning the NW characteristics. The seed layers on carbon cloth produce NWs with highly enhanced electrochemically active surface area, which would show efficient electrochemical CO2 reduction. In addition, the hierarchical architecture resulted from the seeded growth of NWs on SnO2 nanosheets allows thin layers of BiVO4, forming a heterojunction photoanode, which shows a record charge separation efficiency of 96.6% and a charge-transfer efficiency of 90.2% at 1.23 V versus the reversible hydrogen electrode among, to date, the reported BiVO4-based photoanodes for water oxidation. Our study illustrates that such a versatile interfacial engineering effort by the ALD technique would be promising for further wide range of practical applications.

Efficient Electrochemical Reconstruction of a Cobalt- and Silver-Based Precatalytic Oxalate Framework for Boosting the Alkaline Water Oxidation Performance

“…The XPS spectrum for Co 2p displays two distinct peaks at 781.3 and 797.1 eV, representing Co 2p 3/2 and Co 2p 1/2 , respectively. The appearance of satellite peaks at 785.6 and 801.3 eV further confirms the presence of Co +2 in CoC 2 O 4 /Ag 2 C 2 O 4 . , A narrow scan of the Ag 3d region manifests peaks at 366.8 and 372.8 eV for Ag 3d 5/2 and Ag 3d 3/2 , respectively, with a well-defined separation of 6.0 eV, indicating the existence of Ag +1 in CoC 2 O 4 /Ag 2 C 2 O 4 . , The O 1s spectrum shows peak signals at 530.5 and 532.8 eV, attributing to lattice oxygen and chemisorbed oxygen, respectively. , To further validate the presence of elements, inductively coupled plasma-optical emission spectroscopy (ICP-OES) was conducted, showing Ag/Co = 1:3.6508 for CoC 2 O 4 /Ag 2 C 2 O 4 (Table S1). The morphological features were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) for all the samples (Figure ).…”

“…39,47 To further validate the presence of elements, inductively coupled plasma-optical emission spectroscopy (ICP-OES) was conducted, showing Ag/Co = 1:3.6508 for CoC 2 O 4 /Ag 2 C 2 O 4 (TableS1). The morphological features were investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) for all the samples (Figure2).…”

Hierarchical Nanoporous BiVO4 Photoanodes with High Charge Separation and Transport Efficiency for Water Oxidation

“…38,39 Although this was not a direct determination of the specific surface area, the slope values could be compared to similar photoanodes to determine the difference in surface characteristics. 40,41 It was noted that BV15 exhibited a larger slope value than the other BV electrodes, suggesting that BV15 possessed the maximum ECSA (Figure 4g). It was expected that the increased embedded porosity within the BI nanosheets in BI15 could result in generating a higher surface area of BV15.…”

“…To elucidate the nonlinear changes of the PEC properties, the relative electrochemically active surface areas (ECSAs) of the BV films were estimated from their electrochemical double-layer capacitance ( C dl ), which was found to be linearly proportional to the ECSA. − The difference in current density (Δ J ) of the anodic ( J a ) and the cathodic ( J c ) sweeps (Δ J = J a – J c ) vs scan rate was plotted (Figures g and S8). The linear slope of the plot is equivalent to twice the C dl , and thus, the slope value can be used to estimate the relative changes in the ECSA. , Although this was not a direct determination of the specific surface area, the slope values could be compared to similar photoanodes to determine the difference in surface characteristics. , It was noted that BV15 exhibited a larger slope value than the other BV electrodes, suggesting that BV15 possessed the maximum ECSA (Figure g). It was expected that the increased embedded porosity within the BI nanosheets in BI15 could result in generating a higher surface area of BV15.…”

Nematic‐type Structure of the SnO2(110) Surface at Room Temperature

“…Tin dioxide SnO 2 is widely used as gas sensors and catalysts. [1][2][3][4][5][6] The electrical conductivity of SnO 2 with the rutile structure is sensitive to the gas environment. To understand the process of gas detection and catalytic reaction at an atomic scale, and to improve the sensitivity and selectivity of SnO 2 -based gas sensors and catalysts, the prerequisite is to determine the atomic and electronic structure of the SnO 2 surfaces.…”