The cocatalyst roles of three anionic Cd(II) porphyrinic metal-organic frameworks in the photocatalytic CO2 reduction to CO process carried out in Ru(bpy)3Cl2/CH3CN/H2O/Triethylamine or triethanolamine system

Article abstract of DOI:10.1016/j.jssc.2020.121690

Three 3D, anionic Cd(II) porphyrinic metal-organic frameworks (PMOFs), 1(3.5:1)-2d-120 ([Cd_3·2(H₂TCPP)₂][(CH₃)₂NH₂]_1.6), its Li⁺-exchanged product (e.g. Li⁺-1-120, formula: [Cd_3·2(H₂TCPP)₂]Li_1.6) and 1(10:1)-4d-120 ([Cd_3·7H₂TCPP)₂][(CH₃)₂NH₂]_0.6) were synthesized, all of which have the same PXRD pattern. Their VB and CB band-edge positions were determined in nonaqueous electrolyte as ?0.59, 1.12; ?0.60, 1.11; and ?0.60, 1.16, respectively. Their light absorption properties in the range of 250–2500 ?nm were obtained by UV–Vis-IR reflectance spectroscopy. Transient photocurrent responses, electrochemical impedance spectra (EIS) and solid state photoluminescence (PL) spectra of the three PMOFs were obtained. When irradiated using light of 430 ?nm and ?0.5-0.5 bias potentials (versus Ag/Ag⁺ electrode in CH₃CN), both positive and negative photocurrent were observed. Mott-Schottky plot measurements indicate that they are intrinsic semiconductors. Although these three PMOFs can photocatalytically reduce CO₂ to CO in the absence of Ru (bpy)₃Cl₂, their catalytic abilities are very weak. The roles of these PMOFs in CH₃CN/trimethylamine (TEA) or triethanolamine (TEOA)/H₂O (400 ?μL)/Ru (bpy)₃Cl₂.6H₂O was found to be mainly cocatalysts, and Ru (bpy)₃Cl₂ was the actual photocatalyst in the presence of small amounts of water (0–400 ?μL). These PMOFs act as cocatalysts due to the increased reducing power upon light irradiation. Reducing the charge of the framework can reduce the efficiencies of the photocatalytic CO₂ reduction to CO. Li⁺-1-120 was found to be able to react with Ru (bpy)₃Cl₂ when sufficient amounts of H₂O are present in CH₃CN and TEA system, preventing the photocatalytic property of Ru (bpy)₃Cl₂ to be released. In addition, we found that TEOA is a worse reducing agent than TEA, leading to much lower photocatalytic efficiency of the system. Mechanisms were proposed for reactions occurred in CH₃CN/TEA (or TEOA)/H₂O (400 ?μL)/Ru (bpy)₃Cl₂.6H₂O/PMOF system, and strategies to improve the photocatalytic performance of CO₂ reduction to CO were proposed.

Full text of DOI:10.1016/j.jssc.2020.121690

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JACC March 21, 2017
Volume 69, Issue 11
Prevention
THE PROGNOSTIC VALUE OF CPET: ASSOCIATION WITH CORONARY ARTERY CALCIUM SCORE
Poster Contributions
Poster Hall, Hall C
Saturday, March 18, 2017, 3:45 p.m.-4:30 p.m.
Session Title: Innovations in Cardiovascular Risk Assessment and Reduction
Abstract Category: 32. Prevention: Clinical
Presentation Number: 1235-063
Authors: Matthew Hakimi, Tomohiko Kisaka, Kathy Sietsema, Yasuki Kihara, Karlman Wasserman, Matthew Budoff, Los Angeles
Biomedical Research Institute, Torrance, CA, USA, Hiroshima University Hospital, Hiroshima, Japan
Background: It has been proposed that information derived from cardiopulmonary exercise testing (CPET) may provide additional
prognostic information; but there are few studies evaluating for coronary artery disease (CAD). By measuring a broad range of variables,
CPET can precisely determine aerobic capacity and independent and coupled functions of the cardiovascular, pulmonary and skeletal
muscle systems. We tested the prognostic relevance of CPET by comparing its functional data to coronary artery calcium (CAC) score.
CAC is highly predictive for cardiovascular events and provides unique anatomic information regarding coronary atherosclerotic burden.
Methods: Data from 83 asymptomatic individuals with CAD risk factors were retrospectively analyzed at LA Biomedical Research Institute
and Hiroshima University Hospital. Subjects had an exercise stress test by CPET followed by CAC from 2009 to 2015. An algorithm was
developed using specific CPET parameters (peak VO < 75% of predicted, V /VCO at anabolic threshold (AT) ≥ 34, and delta VO /delta
2
E
2
2
WR slope ≤ 8.3) to physiologically separate individuals into control, ischemic and non-ischemic groups.
Results: Mean CACS in the control group with normal exercise capacity was 196 ± 363. The ischemic group, termed exercise induced
myocardial ischemia (E-IMI), had CACS of 1074 ±1261, while the non-ischemic exercise cardiomyopathy (ECM) group had CAC of 297 ±
4
96. As compared with control and ECM, the mean scores were significantly higher in the E-IMI group (p=0.0007 and 0.0021, respectively).
Multiple logistic regression found that the observed highest CAC was independently associated with the CPET identified ischemic group
(E-IMI) after adjustment for risk factors: sex, age, BMI, diabetes mellitus, hypertension, hyperlipidemia, cigarette smoking, and family
history.
Conclusions: CPET is useful in CAD risk stratification and in identifying patients who may benefit from intensified medical therapy or
coronary angiography for possible revascularization. CPET identifies with high accuracy those with very high CAC, and those exhibiting
ischemia had an average CAC score >1000, which has great prognostic significance as a very high risk cohort.