Pt-Doped and Pt-Supported La_1–xSr_xCoO₃: Comparative Activity of Pt⁴⁺ and Pt⁰ Toward the CO Poisoning Effect in Formic Acid and Methanol Electro-oxidation

Abstract

Pt-supported La1–x Sr x CoO3 and Pt-doped La1–x Sr x CoO3 are synthesized using chemical reduction and solution combustion method, respectively. Chemical reduction is carried out using formaldehyde as a reducing agent giving Pt-supported La1–x Sr x CoO3. Solution combustion method is used to prepare Pt-doped La1–x Sr x CoO3. Detailed characterization using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area measurement, and transmission electron microscopy (TEM) is carried out to distinguish the Pt-supported and Pt-doped compounds in terms of their morphology and Pt oxidations states. TEM results indeed show the differences in their morphology. Further, electrochemical measurements are performed in neutral medium to differentiate their electrochemical activity. Cyclic voltammetry (CV) shows noticeable differences between Pt-supported La1–x Sr x CoO3 and Pt-doped La1–x Sr x CoO3. Importantly, our results show that Pt4+ in doped compound has poor to zero electrocatalytic activity toward formic acid and methanol electro-oxidation in comparison to Pt0 in supported compound. This study shows that metallic Pt in zero oxidation state is a superior catalyst to Pt in +4 oxidation state.

Instant and Persistent Hydrogen Production Using Nano High Entropy Catalyst

“…in HEAs is 1.47, which is about 3.5 times higher than the conventional Pt nanopart icles (0.4). This confirms the major contribution from the direct pathway 12,13,14 . Chronoamperometry at 0. and a noticeable amount of CO ( Figure S2c).…”

“…In the case of HEAs, a well-defined oxidation peak at ~0.69 V with a current value of 4.27 mA is observed, which is related to the oxidation of HCOOH. Similarly, in the reverse scan, an anodic peak at ~0.32 V with a current value of 2.89 mA is observed, which is also attributed to the HCOOH oxidation p receded by the surface reduction 12,13 . The forward and reverse p eak current ratio (i f /i t ) in HEAs is 1.47, which is about 3.5 times higher than the conventional Pt nanopart icles (0.4).…”

Formic acid and methanol electro-oxidation and counter hydrogen production using nano high entropy catalyst

“…The forward and reverse peak current ratio (if/ir) in the HEAs is 1.47, which is about 3.5 times higher than the conventional Pt nanoparticles (0.4). This confirms the major contribution from the direct oxidation pathway [17][18][19]. Chronoamperometry at 0.7 V for 1000 seconds on HEA in an air-tight cell is carried out to analyze the evolved gases (Figure 3c).…”

“…In the case of HEAs, a welldefined oxidation peak at ~0.69 V with a current value of 4.27 mA is observed, which is related to the oxidation of HCOOH. Similarly, in the reverse scan, an anodic peak at ~0.32 V with a current value of 2.89 mA is observed, which can be assigned to the HCOOH oxidation preceded by the surface reduction [17,18]. The forward and reverse peak current ratio (if/ir) in the HEAs is 1.47, which is about 3.5 times higher than the conventional Pt nanoparticles (0.4).…”

A promising carbon fiber-based photocatalyst with hierarchical structure for dye degradation

“…33,34 No characteristic peaks of Pt particles were detected in the diffraction patterns of the composite samples, indicating that Pt particles were in a highly dispersed state or the size of Pt nanoparticles is too small. 35,36 In addition, in contrast to hydrothermal growth, weaker diffraction intensity of ZnO NRs also reveals the existence of Pt species. SEM images of each preparation stage of as-prepared samples are shown in Fig.…”