Figure 5 of the original article contains an error. The error was due to the use of gas-phase NH3 in the calculation of state (i,k‡l). Adsorbed NH3 should have been used instead because this state occurs prior to NH3 desorption. The error resulted in much larger activation barriers for OH attack on acetyl being depicted in the original Figure 5 for the three facets of ceria. They appear comparable to the barriers of acetic acid desorption, which is inconsistent with the conclusion that product desorption is rate-limiting in this reaction at ambient temperature.
Figure 5.
Minimum-energy reaction energy profiles for deamidation and hydrolysis of acetamide on (111), (110), and (100) facets (a-c) respectively, calculated using GGA-PW91 (black circles, VASP), optB86b-vdW (red squares, QE), and optB86b-vdW+SCCS (blue triangles, QE). The reaction states are (a) acetamide, water; (b) η1 acetamide; (b‡c) TS of nucleophilic attack by Olatt; (c) TI; (c+f) TI + H2O; (c+f‡h) TS of C–N scission + H2O; (c+g) TI + OH + H; (c+g‡d+g) TS of C–N scission + OH + H; (d+g) acetyl + NH2 + OH + H; (d+g‡h) TS of NH2 hydrogenation; (h) acetyl + NH3 + OH; (i,k‡l) NH3, TS of OH attack; (i,l) NH3, acetate + H; (j,l) NH3 desorbed; and (j,m) acetic acid desorbed. Labels correspond to those in Table 2. Hollow blue triangle in each panel corresponds to aqueous NH4+ and CH3COO–. The optB86b-vdW profile, when calculated using VASP (not shown), differs from QE (red squares) by 0.11 eV or less.
The corrected version is shown below with the same caption as before. State (i,k‡l) is now revised to include NH3 adsorbed at infinite separation from the transition state k‡l. As can be seen, and as can be verified with entry k → l, Table 2 of the original article, the OH attack is not a kinetically relevant step in this reaction. All other states in Figure 5 have the correct energies.
Author Present Address
† SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA