Gas flow Stimulated Hydrodynamics for Preparation and Application of Platinized Titanium Hollow Fibre Electrodes

Abstract

In this study, Pt was electrodeposited on the surface of Ti hollow fibres from PtCl 6 2À solution at fixed potential and at variable gas flow rate. Partial Pt coverage of Ti was obtained at flow rates � 5 mL•min À 1 , while a more-even geometrical distribution and linearly increasing Electrochemical Surface Area (ECSA) of Pt was obtained for flow rates of > 5 and < 20 mL•min À 1 . Above 20 mL•min À 1 , the morphology did not significantly change, and only a limited increase in ECSA of Pt (Pt ECSA ) was observed. Second, the performance of the Pt functionalized Ti-HFEs was evaluated at fixed potential in i) liquid phase oxidation of Fe II to Fe III , and ii) the hydrogen (gas) evolution reaction (HER). Generally, for the oxidation of Fe-(CN) 6 4À , a linear increase in current from 3 to � 9 mA was found as a function of increasing gas flow rate. For the HER, a gas evolving reaction, initially (in the range of 0-10 mL•min À 1 ) a much larger enhancement in current (from �-10 to À 35 mA) was observed than consecutively at higher flow rates. The effect of gas flow rate on Pt deposition, and utilization of platinized Ti HFEs, is explained on the basis of increasing fractional participation of relatively small pores at high flow rates, and generally an increasing mass transfer coefficient (k M ) associated with localized mixing of the electrolyte near the electrode/ electrolyte interface. The k M is roughly in the same order of magnitude as obtained in experiments using rotating disc electrodes.

Electro-oxidation of propylene by palladium functionalized titanium hollow fibre electrodes

“…Inspired by the publication of Winiwarter et al [14], now we evaluate Pd functionalized Ti electrodes in hollow fibre geometry in selective oxidation of propylene, to assess if intensification of the triple phase boundary will lead to improved performance (as previously reported for cathodic reduction of CO 2 and conversion of nitrogen oxides) [24][25][26][27][28][29], and prevents formation of CO 2 (reaction ( 1)) [30][31][32][33][34]. The electrodeposition of Pd on the Ti HF (varying current and pressure) and the resulting composition and morphology (SEM, XPS, porometry, cyclic voltammetry) are discussed.…”

Electrochemical CO2 conversion with a flow-through copper hollow fibre: A process parameter evaluation

“…[17] Similar observations are done in case of platinum deposition on titanium hollow fibres. [102] It is recommended to reproduce these experiments, while supplying the nickel or platinum containing electrolyte through the inside of the fibre, to show if the electrochemical active surface area extends more to the inside of the fibre wall when the entire pore structure is filled with an electrochemical active specie.…”

“…It is recommended to study the effect of bubble distribution on the fibre's electrocatalytic activity. Although this has been investigated already for titanium hollow fibre electrodes, [102] it is likely that the pore size distribution of the copper hollow fibres is different compared to the pore size distribution of the titanium hollow fibres, which results in a different bubble distribution.…”