## 1 Introduction  
Formic acid (FA) is a valuable chemical product that is difficult to replace in certain applications. Its strong acidic and reducing properties make it useful in agriculture, pharmaceutics, food, textiles, and chemicals. FA has recently been suggested as a promising hydrogen storage component via its decomposition to CO\({}_{2}\) and H\({}_{2}\) with a possible reversible transformation back to regenerate formic acid, which serves as a platform for chemical energy storage [1]. The conventional production processes of FA are based mainly on fossil fuels utilization. Production processes of formic acid can be classified into four groups: methyl formate hydrolysis, oxidation of hydrocarbons, hydrolysis of formamide, and preparation of formic acid from formates. Among them, the methyl formate-based process route is currently dominant [2]. Worldwide formic acid production capacity by hydrolysis of methyl formate was estimated at 770 kton\(\cdot\)year\({}^{-1}\) in 2014, covering approximately 90% of the overall installed capacity. This process involves a carbonylation of methanol and subsequent hydrolysis of the methyl formate that is produced. Carbon dioxide (CO\({}_{2}\)) emissions during the production of FA that use hydrolysis of methyl formate came from the required steam and syngas productions in the upstream processing. Syngas is needed as CO in order to react with methanol; it may come from steam reforming of light ends, as natural gas, from partial oxidation of fossil feedstocks or from coal gasification [3]. Limitations of the FA conventional process can include slow reaction rate, undesirable by-products, high cost of investment, and issues related to the environment such as the high energy requirements (in the separation stage) and a noticeable dependence on fossil fuel (heavy fuel oil is used in the synthesis of CO) [4]. Thus, in parallel to the alarming issue of the global warming and climate change, the depletion of the mentioned fossil fuels, which must remain underground for generations to come, may seem less evident. Therefore, it is not surprising that nowadays the utilization of CO\({}_{2}\) is gaining momentum in the scientific community and the industrial corporations in order to shift from conventional fossil-based processes toward environmentally-friendly processes. In that context, CO\({}_{2}\) could be a feedstock for the production of a wide variety of fuels and commodities including FA. The concept, known as CO\({}_{2}\) valorisation, offers a potential solution directed towards the pursuit of mitigation targets set by the COP21 Paris Agreement to abate the problem of the greenhouse effect [5]. Undoubtedly, it cannot be claimed that climate change will be solved merely by the utilization of CO\({}_{2}\) to FA or any other reduced form of CO\({}_{2}\) such as methanol, syngas, methane, ethylene, etc., but the exploration of new alternatives to fossil-based production routes shows a potential pathway with which to contribute to the curbing of CO\({}_{2}\) emissions. Some of the main available processes to convert CO\({}_{2}\) into FA are homogeneous catalysis [6; 7; 8], heterogeneous catalysis [9; 10; 11; 12], photocatalytic reduction [13], and electrochemical reduction (ER) [14; 15], which share a substantial input of energy per unit of reduced CO\({}_{2}\)[6]. These CO\({}_{2}\) utilization technologies for production of FA are currently found at different stages in terms of maturity. The alternatives should be economically viable, safe, and sustainable for their final industrial commercialization. The efforts are mainly focused on decreasing the overall energy consumption of the processes. On one hand, thermocatalytic synthesis of FA from CO\({}_{2}\) and H\({}_{2}\) may be easily adopted due to it being based on currently available technology; however, it needs a high heat input or a heat integration [7].