according to my knowledge Ethyldimethylsilane and a ruthenium catalyst were used to reduce aliphatic carboxylic acids to the corresponding alcohol.. With tris(pentafluoro phenyl)borane as catalyst, triethylsilane reduces carboxylic acids to the alkane. you can check this link please . 

http://www.azmax.co.jp/cnt_catalog_chemical/pdf/attach_20110517_112436.pdf

In the case of graphene oxide, solvothermal treatment in basic medium (ammonia) should be good enough to remove oxygen functional groups.  

we can reduce -COOH groups at their homologues Methyl ester or propyl ester by esterification using BF3 in propanol and heating at 70 °C (to obtain propyl ester)