Direct conversion of methane to formaldehyde and CO on B(2)O(3) catalysts

Direct oxidation of methane to value-added C(1) chemicals (e.g. HCHO and CO) provides a promising way to utilize natural gas sources under relatively mild conditions. Such conversions remain, however, a key selectivity challenge, resulting from the facile formation of undesired fully-oxidized CO(2). Here we show that B(2)O(3)-based catalysts are selective in the direct conversion of methane to HCHO and CO (~94% selectivity with a HCHO/CO ratio of ~1 at 6% conversion) and highly stable (over 100 hour time-on-stream operation) conducted in a fixed-bed reactor (550 °C, 100 kPa, space velocity 4650 mL g(cat)(−1) h(−1)). Combined catalyst characterization, kinetic studies, and isotopic labeling experiments unveil that molecular O(2) bonded to tri-coordinated BO(3) centers on B(2)O(3) surfaces acts as a judicious oxidant for methane activation with mitigated CO(2) formation, even at high O(2)/CH(4) ratios of the feed. These findings shed light on the great potential of designing innovative catalytic processes for the direct conversion of alkanes to fuels/chemicals.