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Abstrak :
Reaksi hidrogenasi CO2 dilakukan melalui katalis bimetalik Ni-Ga dan Ni-Ga termodifikasi Ag yang didukung pada karbon mesopori (MC). MC berhasil disintesis menggunakan metode soft-template dengan menggunakan phloroglucinol sebagai prekursor karbon dan pluronik F-127 sebagai template. Katalis Ni-Ga dan Ni-Ga yang termodifikasi Ag disintesis menggunakan metode impregnasi dengan variasi Ni5Ga3/MC, Ni5Ga3Ag0,1/MC, Ni5Ga3Ag0,3/MC, dan Ni5Ga3Ag0,5/MC. Berdasarkan karakterisasi XRD, pembentukan bimetal Ni-Ga dan nanopartikel Ag pada penyangga MC telah terkonfirmasi. Gambar mapping EDX menunjukkan Ni-Ga maupun NiGa-Ag terdistribusi secara merata pada permukaan MC. BET-SAA menunjukkan ukuran diameter pori katalis Ni5Ga3/MC dan Ni5Ga3Ag0,1/MC masing-masing adalah 5,5 nm dan 6,0 nm yang mana termasuk dalam ukuran mesopori 2-50 nm. Aktivitas katalis dalam reaksi hidrogenasi CO2 dilakukan pada reaktor fixed-bed. Pada katalis Ni5Ga3/MC dan Ni5Ga3Ag/MC terdeteksi produk metanol dan formaldehida. Penambahan Ag pada katalis Ni5Ga3/MC meningkatkan konversi CO2 dan yield produk metanol maupun formaldehida pada katalis Ni5Ga3Ag0,1/MC. Yield optimum metanol dan formaldehida dihasilkan dengan rasio H2/CO2 7/1 pada suhu 170 °C yaitu masing-masing 0,02 dan 2,26%.. Konversi CO2 semakin kecil dengan semakin meningkatnya suhu reaksi karena kondisi reaksinya yang eksoterm. ......The study of CO2 hydrogenation reaction was carried out using bimetallic Ni-Ga and Ag-modified Ni-Ga catalysts supported on mesoporous carbon (MC). MC was successfully synthesized using the soft-template method by using phloroglucinol as a carbon precursor and pluronic F-127 as a template. The Ni-Ga and Ag-modified Ni-Ga catalysts were synthesized using the impregnation method with variations in Ag loading to give Ni5Ga3/MC, Ni5Ga3Ag0.1/MC, Ni5Ga3Ag0.3/MC, and Ni5Ga3Aug0.5/MC catalyst. Based on the characterization of XRD, the formation of bimetallic Ni5Ga3 and Ag nanoparticles on MC have been confirmed. The EDX mapping image shows both Ni-Ga and NiGa-Ag were evenly distributed on the MC surface. BET-SAA analysis shows the pore diameter of Ni5Ga3/MC and Ni5Ga3Ag0.1/MC catalysts are 5.5 nm and 6.0 nm respectively which are included in the mesoporous size of 2-50 nm. The activity of the catalyst in the hydrogenation reaction of CO2 was carried out in a fixed-bed reactors. Both Ni5Ga3/MC and Ag-modified Ni5Ga3/MC catalysts gave methanol and formaldehyde as CO2 hydrogenation products. The addition of Ag to the Ni5Ga3/MC catalyst increases the CO2 conversion and yield of methanol and formaldehyde products. The highest yield of methanol of 0.02% and formaldehyde of 2.26% were obtained over Ni5Ga3Ag0.1/MC catalyst with a H2/CO2 ratio of 7/1 at 170 °C. The conversion of CO2 is getting smaller with increasing reaction temperature due to its exothermic reaction conditions.

Abstrak :
Reaksi karboksilasi fenilasetilena dengan CO₂ dilakukan dengan menggunakan katalis Ni-Ga dan Ni-Ga termodifikasi timah (Sn) yang disangga oleh karbon mesopori (MC). MC disintesis dengan metode soft template dan dianalisis dengan TGA diperoleh kestabilan termal hingga 850 °C. Katalis dikarakterisasi dengan FTIR, XRD, Raman, SEM, TEM, dan BET. Hasil XRD menunjukkan puncak pada 24,47°; 32,73°; 43,83°; 50,96°; 74,32°yang merupakan difraksi Ni₅Ga₃ dan partikel Sn(0) pada penyangga MC. Penambahan Sn diketahui tidak mengubah kestabilan katalis Ni₅Ga₃/MC yang dikonfirmasi melalui FTIR dan Raman. Hasil SEM dan TEM juga menunjukkan partikel Ni-Ga-Sn tersebar merata pada permukaan karbon mesopori. BET menunjukkan katalis termasuk dalam ukuran mesopori 2-50 nm. Uji aktivitas katalitik berdasarkan analisa HPLC menunjukkan hasil optimum diperoleh dengan menggunakan katalis Ni₅Ga₃Sn₀‚₅/MC pada suhu 50°C selama 8 jam. Sedangkan berdasarkan LC-MS, diketahui terbentuk produk asam sinamat dan asam fenil propiolat dengan yield masing-masing 2,14% dan 3,04% dengan konversi fenilasetilena mencapai 93,06%. ......The carboxylation reaction of phenylacetylene with CO2 was carried out using Ni-Ga and Ni-Ga-modified tin catalysts supported by mesoporous carbon (MC). MC was synthesized using the soft template method and analyzed using TGA and obtained thermal stability up to 850 0C. To determine the modification effect of Sn addition, catalysts were synthesized with variations of Ni5Ga3/MC, Ni5Ga3Sn0.1/MC, Ni5Ga3Sn0.3/MC, Ni5Ga3Sn0.5/MC, Ni5Ga3Sn0.7/MC, Ni5Ga3Sn0.9/MC. The catalysts were characterized by FTIR, XRD, Raman, SEM, TEM, and BET. XRD results show peaks at 24.47o; 32.73 o; 43.83o; 50.96 o; and 74.32o which is the diffraction of the Ni5Ga3 phase and Sn (0) particles on the MC support. The addition of Sn metal is known not to change the stability of the Ni5Ga3/MC catalyst which was confirmed through FTIR and Raman spectra. SEM and TEM results also show that Ni-Ga-Sn particles are evenly distributed on the mesoporous carbon surface with a spherical shape. BET-SAA shows the pore diameter size of the materials Ni5Ga3/MC, Ni5Ga3Sn0.1/MC, Ni5Ga3Sn0.3/MC, Ni5Ga3Sn0.5/MC, Ni5Ga3Sn0.7/MC, Ni5Ga3Sn0.9/MC respectively, are 6.24 nm; 6.22nm; 7.22nm; 6.24 nm, 7.22 nm, and 10.46 nm which are included in the mesopore size of 2-50 nm. The catalytic activity test was carried out through the carboxylation reaction of phenylacetylene with CO2 using variations of catalyst, time and temperature. HPLC analysis showed that optimum results were obtained using the Ni5Ga3Sn0.5/MC catalyst at a temperature of 500C for 8 hours. Meanwhile, based on LC-MS, it is known that cinnamic acid and phenyl propiolic acid products were formed with yields of 2.14% and 3.04% respectively with 93.06% phenylacetylene conversion.