Reduced CO2 on a polycrystalline Rh electrode in acid solution: electrochemical and in situ IR reflectance spectroscopic studies

Electrochemical study on the adsorption of carbon oxides and oxidation of their adsorption products on platinum group metals and alloys

“…[33][34][35][36]43,44,[51][52][53][54][55][57][58][59][60] However, some other adsorbates were also postulated like COH, 35,44,45,49 CHO 48 and COOH radicals, 33,35,[37][38][39][40]46,50,52,60 although these species have not been confirmed by most IR spectroscopy data. 43,51,55,59 In the case of an Rh electrode the adsorption product of CO 2 reduction is more reduced than on Pt 41,42,54,56 and a CO-type adsorbate is probably accompanied by a reduced form of adsorbed CO 54,56 or such species as CHO, 42 COH, 42,60 CH 2 , 41 CH 42 or even C radicals. 42 In comparison with CO 2 , the behavior of CO towards platinum group metals is markedly different.…”

“…61,[63][64][65][66][68][69][70][71][72] In the literature there is no agreement whether the adsorption products of CO 2 reduction on Pt and Rh are identical with the products of a direct CO adsorption. According to some authors 34,43,59 both adsorbates are the same, while other workers 46,54,56,58,62,67,[73][74][75][76] believe that reduced CO 2 cannot be totally identified with adsorbed CO.…”

Comparative EQCM study on electrooxidation of carbon oxides adsorption products on noble metals and their alloys. Polycrystalline Pd-based systems

“…It was also postulated that CO 2 molecules only block hydrogen atoms, becoming blocked itself by water molecules and anions [26,44,46,51]. In the case of Rh electrode the adsorption product of CO 2 reduction is regarded as generally more reduced than on Pt [34,35,37,52,54]. A mixture of a CO-type adsorbate is proposed, probably with an addition of a reduced form of adsorbed CO [52,54] or such species as COH [35,59], CH 2 [34], CH [35] or even C radicals [35].…”

“…The process of CO 2 electrosorption on Pt and Rh depends on such factors as: potential and time of adsorption [28][29][30][31][32][33][34][35][38][39][40]45,46,[50][51][52][53][54][55]58,59], electrode surface morphology [41,51,55], method of electrode pretreatment [51,55] and solution composition [39,46,51,53,54] as well as plane orientation for single crystal electrodes [73][74][75][76][77][78]. The results of earlier experiments performed on noble metal alloys [6,[79][80][81][82][83][84] have showed that in general the surface coverage, structure and composition of the adsorption product are dependent on the alloy surface composition.…”

Electrochemical quartz crystal microbalance study on carbon oxides adsorption in the presence of electrosorbed hydrogen on Pd alloys with Pt and Rh

“…When eps is higher than 2 (for a Pd-Rh alloy) additional products might be proposed, such as multi-bonded C-H or C-OH species, suggested earlier for Rh electrodes [4,18,42]. It has been confirmed spectroscopically that on Rh electrodes some additional CO 2 adsorption products exist which are more reduced than adsorbed CO [28]. The differences in eps values for CO 2 and CO adsorption, higher for the Pd-Pt than Pd-Rh system, indicate that the products of both carbon oxides adsorption might not be the same.…”