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Desirable catalysts possessing the ability to selectively break C–H bond and controllably catalyze C–C bond formation are highly demanded for the nonoxidative coupling of methane (NOCM). Herein, a series of Pt-Cu alloy catalysts including Pt1©Cu(111), Pt2©Cu(111) and Pt3©Cu(111) are deliberately designed and systematically studied for NOCM. Density functional theory calculations reveal that the Pt1, Pt2, and Pt3sites on Cu(111) can selectively break the C–H bond to generate CH3, CH2, and CH species, respectively. However, direct coupling of corresponding CHx(x= 3, 2, 1) to form C2H6, C2H4, and C2H2are favorable on Pt3, Pt1, and Pt2sites on Cu(111), respectively. The different reactivity trends of the three Pt sites mainly originate from the varying bonding abilities of CHxspecies at the Pt sites. Microkinetic modeling manifests that the Pt1©Cu(111) is the most active for methane dissociation (TOF = 2.98 s–1at 1000 K) and can selectively convert methane into ethylene with the highest selectivity up to 96.2% at 750 K. Moreover, Pt1©Cu(111) also shows superb stability under reaction conditions. Overall, our studies not only provide a comprehensive understanding of the reaction mechanism of NOCM on Pt single-atom sites (SASs) and Pt single-cluster sites (SCSs) but also predict that Pt SASs are advantageous over Pt SCSs for NOCM.

The remote sensing measurement of the surface SiO2 content has important geological significance .An empirical formula for estimate SiO2 content was established based on the correlation between ASTER thermal infrared data and tested Si element from NITON sites in Abra, Australia. The average error of estimated SiO2 content is about 15%. ASTER silica alteration derived from SiO2 content has good indicative function to find galena. Combined with other prospecting factors as bouger gravity, transient electromagnetic and so on, three vision prospecting targets were optimized, which need more exploration works.