When using temporal adjuncts (extra bits of information at the end of the sentence about when something happened), we often use the prepositions in, on or at with a noun phrase afterwards:
- I will see you on Tuesday.
- It happened in the afternoon.
- At Christmas my parents came to stay.
However, when we use the words this, that, next or last with these nouns, we don't usually use another preposition:
- I will see you next Sunday.
- It happened that afternoon.
- Last Christmas my parents came to stay.
- *I will see you on next Sunday. (X)
- *It happened in that afternoon. (X)
- *At last Christmas my parents came to stay. (X)
We also don't usually use prepositions with time words that begin with to- or yester-. This may be because the prefixes to- and yester- mean something like this and last:
- *I'll see you on tomorrow. (X)
- *I saw him on yesterday. (X)
- *I'll see you at tonight. (X)
The Original Poster's Question
She's won five rewards this year.
She's won five rewards in this year. (X)
The first example is fine. The second one is awkward because it uses in and this together. If we didn't use this then we could use a preposition with the year:
- She won five awards in 2014.
For the Original Poster's verb-less phrase the best option is:
Hope this is helpful!