Investigating the platinum electrode surface during Kolbe electrolysis of acetic acid

Platinum is commonly applied as the anode material for Kolbe electrolysis of carboxylic acids thanks to its superior performance. Literature claims that the formation of a barrier layer on the Pt anode in carboxylic acid electrolyte suppresses the competing oxygen evolution and promotes anodic decarboxylation. In this work, we show by using a combination of complementary in situ and ex situ surface sensitive techniques, that the presence of acetate ions also prevents the formation of a passive oxide layer on the platinum surface at high anodic potentials even in aqueous electrolyte. Furthermore, Pt dissolves actively under these conditions, challenging the technical implementation of Kolbe electrolysis. Future studies exploring the activity-structure-stability relation of Pt are required to increase the economic viability of Kolbe electrolysis

Prognostic role of cardiac calcifications in primary prevention: A powerful marker of adverse outcome highly dependent on underlying cardiac rhythm

BACKGROUND: Increasing evidence exists regarding calcium detected in aortic cusps and/or mitral annulus (AOC_MAC) at transthoracic echocardiogram as a predictor of cardiovascular (CV) events and mortality. PURPOSE: To verify whether AOC_MAC has a prognostic role in the setting of primary prevention independently of the presence of atrial fibrillation (AF). METHODS: All subjects consecutively referred from January 2011 to October 2014 to the Cardiovascular Centre for CV risk assessment in primary prevention were selected. AOC_MAC was assessed by transthoracic echocardiography. Primary study endpoint was a composite of CV hospitalizations/all-cause death. RESULTS: The 1389 study patients were 70\u202fyears old, 43% males, 24% had diabetes mellitus, 75% arterial hypertension, 56% dyslipidaemia. Of all, 997 (72%) were in sinus rhythm (SR), 392 (28%) in AF. Patients with AF were older and more frequently males, with larger atria than SR subjects. During a median follow-up of 32\u202fmonths, 165 patients (12%) were hospitalized for CV cause, 68 (5%) died. The primary endpoint occurred more frequently in patients with than without AOC_MAC (18% vs 11%, p\u202f<\u202f0.001). AF patients showed higher event-rate compared with patients in SR (20% vs 10%, respectively; p\u202f<\u202f0.01). AOC_MAC emerged as an independent prognosticator of primary endpoint in SR patients (HR 1.74 [1.07-2.82], p\u202f=\u202f0.02), together with increasing age and left ventricular hypertrophy, while AOC_MAC had no prognostic relevance in AF patients. CONCLUSIONS: In subjects with multiple CV risk factors assessed in primary prevention, the presence of AF nullifies the prognostic power of AOC_MAC, on the contrary robustly confirmed in SR patients