01969nas a2200265   4500008004100000022001400041245014300055210006900198260000900267300001600276490000700292520103800299653002001337653001801357653001901375653001301394653001901407100002101426700002801447700001701475700002101492700002901513700003001542856013101572       2020                        eng d  a1944-824400aCan half-a-monolayer of pt simulate activity like that of bulk pt? solar hydrogen activity demonstration with quasi-artificial leaf device0 aCan halfamonolayer of pt simulate activity like that of bulk pt   cJUL   a30420-304300 v123 a<p>Pt is the best cocatalyst for hydrogen production. It is also well-known that the surface atomic layer is critical for catalysis. To minimize the Pt content as cocatalyst, herein we report on half-a-monolayer of Pt (0.5 theta(Pt)) decorated on earth-abundant Ni-Cu cocatalyst, which is integrated with a quasiartificial leaf (QuAL) device (TiO2/ZnS/CdS) and demonstrated for efficient solar hydrogen production. For the QuAL, TiO2 is sensitized with ZnS and CdS quantum dots by the SILAR method. The 0.5 theta(Pt)-decorated Ni-Cu shows an onset potential of 0.05 V vs reversible hydrogen electrode for the hydrogen evolution reaction, which is almost similar to that of commercial Pt/C. Photoactivity of the present QuAL device with either bulk Pt or 0.5 theta(Pt)-coated Ni-Cu cocatalyst is, surprisingly, equal. Our findings underscore that a fraction of a monolayer of Pt can enhance the activity of the cocatalyst, and it is worth exploring further for the high activity associated with atomic Pt and other noble metals.</p>
10aartificial leaf10anickel-copper10aPhotocatalysis10aplatinum10aSolar hydrogen1 aBajpai, Himanshu1 aPatra, Kshirodra, Kumar1 aRanjan, Ravi1 aNalajala, Naresh1 aReddy, Kasala, Prabhakar1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/can-half-monolayer-pt-simulate-activity-bulk-pt-solar-hydrogen-activity-demonstration-quasi02553nas a2200265   4500008004100000022001400041245009700055210006900152260000800221300001100229490000800240520168600248653002701934653002801961653000901989653000801998653002002006100001702026700002102043700001602064700002302080700002602103700003002129856012802159       2023                        eng d  a1385-894700aCo3O4 for sustainable CO2 reduction and possible fine-tuning towards selective CO production0 aCo3O4 for sustainable CO2 reduction and possible finetuning towa  cSEP  a1444590 v4713 a<p>Two main challenges involved in heterogeneous catalytic CO2 reduction are: (a) decreasing the consumption of H2 to the minimum required level with possibly the maximum CO2 conversion, and (b) concurrently enhancing the selectivity of the desired CO, at the cost of methane. Towards meeting these two challenges, Co3O4 spinel has been identified as a potential catalyst and it exhibits predominant CO selectivity &gt; 673 K at atmospheric pressure. CO2 conversion begins &gt; 523 K, with 100% CO selectivity observed &gt; 673 K with CO2:H2 = 3:2. Current work shows a sustainable catalytic CO2 conversion to 100% CO selectivity with Co3O4-Nanocube (NC). Critically, CO selectivity and yield is observed to increase at the cost of methane with smaller amount of H2. 1:1 and 3:2 CO2:H2 ratio exhibits 88-100% CO selectivity with 24-32.5% CO2 conversion between 623 and 823 K. Irrespective of the input CO2:H2, ratio of CO2:H2 uptake changes from around 1:3 at 523 K to 1:1-1.5 at 823 K with concurrent production of significant methane to predominant CO, respectively. Surface electronic state changes was explored by near ambient pressure photoelectron spectroscopy, and the results suggests that Co3O4 is the active phase that promotes CO2 reduction selectively to CO. Broadening observed with the vibrational feature of the CO2 molecules at high temperature underscores the heterogeneous character of the catalyst surface, under operating conditions, due to changing electron density. By optimizing the gas hourly space velocity (GHSV), H2-lean CO2:H2 ratio, and the reaction temperature/pressure, 100% CO selectivity could be broadened to a range of operating conditions.</p>
10aCarbon neutral economy10aheterogeneous catalysis10aRWGS10aSDG10aSurface Science1 aRanjan, Ravi1 aTekawadia, Jyoti1 aJain, Ruchi1 aMhamane, Nitin, B.1 aRaja, Thirumalaiswamy1 aGopinath, Chinnakonda, S.  uhttps://library.ncl.res.in/content/co3o4-sustainable-co2-reduction-and-possible-fine-tuning-towards-selective-co-production