TY - JOUR
T1 - Reduction of CO2 with KBH4 in solvent-free conditions
AU - Picasso, Carolina V.
AU - Safin, Damir A.
AU - Dovgaliuk, Iurii
AU - Devred, François
AU - Debecker, Damien
AU - Li, Hai Wen
AU - Proost, Joris
AU - Filinchuk, Yaroslav
N1 - Funding Information:
The authors thank FNRS ( CC 1.5169.12 , PDR T.0169.13 , EQP U.N038.13 ) for financial support. We acknowledge WBI for the incoming postdoctoral fellowship for D. A. Safin and the Fonds Spéciaux de Recherche (UCL) for funding of the PhD fellowship of I. Dovgaliuk, and for the bridge funding for C. V. Picasso. We thank ESRF (Grenoble, France) for the beam time allocation at the SNBL, as well as PSI for the beam time at the MS beamline at SLS. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007–2013) under grant agreement n. 312284 (CALIPSO). This work was partially supported by the COST Action MP1103 “Nanostructured materials for solid-state hydrogen storage”. We thank JSPS KAKENHI Grant Number 15K14168 and JSPS Invitation Fellowship for the short term research in Japan and the International Institute for Carbon Neutral Energy Research ( WPI-I2CNER ), sponsored by the Japanese Ministry of Education, Culture, Sports, Science and Technology . Mrs. Sabine Bebelman is thanked for her help with TGA-FTIR measurements.
PY - 2016/8/24
Y1 - 2016/8/24
N2 - Metal hydrides have been commonly used as reducing agents in organic and inorganic chemistry. Until today, the capability of potassium borohydride (KBH4) to reduce aldehydes and ketones to alcohols has been known for its advantage of high stability on air and in alkaline solutions. Conversion of CO2 to formates and boron methoxide compounds by metal borohydrides has been recently studied. In this work we investigated the solid–gas non-catalytic reaction between KBH4 and CO2 under both mechanochemical and thermal-induced conditions with the simultaneous formation of potassium formylhydroborates, K[HxB(OCHO)4 − x] (x = 1–3), as main products. The first crystal structure of a product of solid–gas metal borohydride – CO2 reaction, potassium triformylhydroborate, K[HB(OCHO)3], obtained mechanochemically, was elucidated. The evolution of the reaction between solid KBH4 and CO2 was monitored by a combination of thermogravimetric analysis coupled with mass spectrometry and infrared spectroscopy from room temperature to 500 °C, revealing the generation of hydrogen, methanol and carbon monoxide in a three-step mass increase reaction. Variable temperature in situ synchrotron X-ray powder diffraction under CO2 pressure revealed the formation of a new crystalline intermediate phase with an unidentified composition but crystallizing in a monoclinic space group, and KBO2 during the second and third steps, respectively. Gas chromatography of evolving species under CO2 flow revealed for the first time the formation of methanol and methane in water-free conditions.
AB - Metal hydrides have been commonly used as reducing agents in organic and inorganic chemistry. Until today, the capability of potassium borohydride (KBH4) to reduce aldehydes and ketones to alcohols has been known for its advantage of high stability on air and in alkaline solutions. Conversion of CO2 to formates and boron methoxide compounds by metal borohydrides has been recently studied. In this work we investigated the solid–gas non-catalytic reaction between KBH4 and CO2 under both mechanochemical and thermal-induced conditions with the simultaneous formation of potassium formylhydroborates, K[HxB(OCHO)4 − x] (x = 1–3), as main products. The first crystal structure of a product of solid–gas metal borohydride – CO2 reaction, potassium triformylhydroborate, K[HB(OCHO)3], obtained mechanochemically, was elucidated. The evolution of the reaction between solid KBH4 and CO2 was monitored by a combination of thermogravimetric analysis coupled with mass spectrometry and infrared spectroscopy from room temperature to 500 °C, revealing the generation of hydrogen, methanol and carbon monoxide in a three-step mass increase reaction. Variable temperature in situ synchrotron X-ray powder diffraction under CO2 pressure revealed the formation of a new crystalline intermediate phase with an unidentified composition but crystallizing in a monoclinic space group, and KBO2 during the second and third steps, respectively. Gas chromatography of evolving species under CO2 flow revealed for the first time the formation of methanol and methane in water-free conditions.
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U2 - 10.1016/j.ijhydene.2016.04.052
DO - 10.1016/j.ijhydene.2016.04.052
M3 - Article
AN - SCOPUS:84977499487
VL - 41
SP - 14377
EP - 14386
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
SN - 0360-3199
IS - 32
ER -