558
1 Introduction
The current human activities depend largely on energy, and their annual consumption of crude oil is expected to be 68% higher by 2030. The recent IEA (International
Energy Agency) reported the worldwide oil demand averaged 96.9 million barrels a
day previous year and will hike to 105.4 million a day in 2030 as projected. Demand
will reach 106.4 million barrels a day in 2040 [1]. Steady energy supply from
numerous energy sources and moves to renewable energies are essential to sustain
the activities of mankind. Concurrently, solutions to global environmental problems
are needed. With mounting concerns on energy safety, environmental pollution, and
potential oil supplies, the universal community is in quest of nonpetroleum-based
alternative fuels, along with more sophisticated energy technologies (e.g., fuel cells)
to increase the competence of energy usage. The most promising alternative fuel
will be having the supreme impact on the society. The major affected areas comprise
well-to-wheel greenhouse gas emissions, fuel versatility, non-petroleum feedstocks,
infrastructure, economics, safety, and availability.
The energy demand is rapidly increasing on the global platform because of the
fast economic growth. In order to pacify this growing demand, a plentiful quantity
of fossil fuel (coal, natural gas, and oil) is needed. India, with its abundant coal
reserves, projects a substantial potential to meet this energy demand. However,
combustion of coal poses a significant problem of NOx, SOx, and particulate matter
emissions [2]. Also, the high ash content (35–40% of the total weight) of Indian coal
affects the thermal power plants efficiency [3]. Moreover, CO 2 emission from direct
coal combustion is a major challenge for sustainability of coal-fired power plants
[4]. Thus, there is an immediate need for development of alternative technologies
for electricity generation from the coal. The history of synthetic fuel is long, beginning in the 1930s with the creation of artificial petroleum from coal and continuing
into the present day as GTL (gas to liquid)/CTL (coal to liquid) technology.
Recently, coal gasification to syngas (a mixture of CO, CO 2 , and H 2 ) has drawn
significant attention over coal combustion of research community worldwide by
suppressing pollutant emissions [5, 6].
Research on conversion of syngas to value-added fuels and chemicals secures the
ability of future generations to meet their energy demands. The use of syngas as an
intermediate in the production of many compounds is presented in the Fig. 1.
Among these products, methanol has potential to replace fossil fuels (diesel, petrol)
for transportation use and thus plays a prominent role in our future economy [7, 8].
Over the past several years, enormous efforts have been put into the improvement of stable and active heterogeneous catalysts for carbon oxides hydrogenation
to methanol. A number of prominent publications have reviewed the technical
aspects related to the catalysis for methanol [9]. Apart from heterogeneous catalysis, many other approaches such as homogeneous catalysis, thermocatalytic, photocatalytic, biocatalytic, electrocatalytic, and photo-electrocatalytic have been used
for carbon oxide conversion to value-added product. However, the challenge in each
approach is the activation of linear CO/CO 2 molecule due to its very high stability.
K. Tripathi et al.
1 Introduction
The current human activities depend largely on energy, and their annual consumption of crude oil is expected to be 68% higher by 2030. The recent IEA (International
Energy Agency) reported the worldwide oil demand averaged 96.9 million barrels a
day previous year and will hike to 105.4 million a day in 2030 as projected. Demand
will reach 106.4 million barrels a day in 2040 [1]. Steady energy supply from
numerous energy sources and moves to renewable energies are essential to sustain
the activities of mankind. Concurrently, solutions to global environmental problems
are needed. With mounting concerns on energy safety, environmental pollution, and
potential oil supplies, the universal community is in quest of nonpetroleum-based
alternative fuels, along with more sophisticated energy technologies (e.g., fuel cells)
to increase the competence of energy usage. The most promising alternative fuel
will be having the supreme impact on the society. The major affected areas comprise
well-to-wheel greenhouse gas emissions, fuel versatility, non-petroleum feedstocks,
infrastructure, economics, safety, and availability.
The energy demand is rapidly increasing on the global platform because of the
fast economic growth. In order to pacify this growing demand, a plentiful quantity
of fossil fuel (coal, natural gas, and oil) is needed. India, with its abundant coal
reserves, projects a substantial potential to meet this energy demand. However,
combustion of coal poses a significant problem of NOx, SOx, and particulate matter
emissions [2]. Also, the high ash content (35–40% of the total weight) of Indian coal
affects the thermal power plants efficiency [3]. Moreover, CO 2 emission from direct
coal combustion is a major challenge for sustainability of coal-fired power plants
[4]. Thus, there is an immediate need for development of alternative technologies
for electricity generation from the coal. The history of synthetic fuel is long, beginning in the 1930s with the creation of artificial petroleum from coal and continuing
into the present day as GTL (gas to liquid)/CTL (coal to liquid) technology.
Recently, coal gasification to syngas (a mixture of CO, CO 2 , and H 2 ) has drawn
significant attention over coal combustion of research community worldwide by
suppressing pollutant emissions [5, 6].
Research on conversion of syngas to value-added fuels and chemicals secures the
ability of future generations to meet their energy demands. The use of syngas as an
intermediate in the production of many compounds is presented in the Fig. 1.
Among these products, methanol has potential to replace fossil fuels (diesel, petrol)
for transportation use and thus plays a prominent role in our future economy [7, 8].
Over the past several years, enormous efforts have been put into the improvement of stable and active heterogeneous catalysts for carbon oxides hydrogenation
to methanol. A number of prominent publications have reviewed the technical
aspects related to the catalysis for methanol [9]. Apart from heterogeneous catalysis, many other approaches such as homogeneous catalysis, thermocatalytic, photocatalytic, biocatalytic, electrocatalytic, and photo-electrocatalytic have been used
for carbon oxide conversion to value-added product. However, the challenge in each
approach is the activation of linear CO/CO 2 molecule due to its very high stability.
K. Tripathi et al.