The selective activation
of targeted bonds in biomass-derived furfural
or furfuryl alcohol with complex chemical linkages (C–C/C–H/C–O,
CC/CO, or C–O–H/C–O–C)
is of great challenge for biomass upgrading, expecting well-defined
catalyst and definite catalytically active sites. This work demonstrates
an efficient targeted activation to C–OH, C–O–C,
or CC by engineering the structure of catalytic Pt sites,
affording 2-methylfuran (2-MF), tetrahydrofurfuryl alcohol (THFA),
or 1,2-pentanediol (1,2-PeD) as product in the hydroconversion of
furfuryl alcohol. The catalytic Pt sites have been engineered as atomic
Pt, coordination unsaturated Pt–Pt in atom-thick dispersion,
or coordination unsaturated 3D Pt–Pt by tailoring the Pt dispersion
(single atom, 2D cluster, or 3D cluster) on Mg and Al-containing layered
double oxide (Mg(Al)O) support. The selective activation of C–OH,
C–O–C, or CC has been traced with the FT-IR
spectra recorded surface reaction. On atomic Pt, C–O–H
is easily activated, with the assistance of Mg(Al)O support, with
O-terminal adsorption without affecting furan C–O and CC.
However, CC in the furan ring is easier to be activated on
coordination-unsaturated Pt–Pt in atom-thick dispersion, resulting
in a step-by-step hydrogenation to generate THFA. On coordination-unsaturated
3D Pt–Pt, the hydrogenolysis of furan ring is favored, resulting
in the cleavage of furan C–O to produce 1,2-PeD. Also, the
Mg(Al)O supports derived from Mg and Al layered double hydroxides
(LDHs) here also play a key role in promoting the selectivity to 1,2-PeD
by providing basic sites.